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SUSE Linux Enterprise Desktop 15 SP6

Modules and Extensions Quick Start

Publication Date: 29 de septiembre de 2024

This Quick Start gives you an overview of the modules and extensions available for the SUSE Linux Enterprise family. Learn about their purpose and features, and how to manage them.

1 Introduction to modules and extensions

Starting with SUSE Linux Enterprise Desktop 15, the installation medium consists of only the Unified Installer: a minimal system for deploying, updating and registering SUSE Linux Enterprise Desktop. During deployment, you can add functionality by selecting modules and extensions to be installed on top of the Unified Installer.

Technically, modules and extensions are very similar. Both can be managed with YaST or the command-line tool SUSEConnect. Both modules and extensions add a set of online repositories (main, update, source, debug) containing all necessary packages. Additionally, both may add partitioning proposals and system roles that can be chosen during deployment.

However, there are significant differences between modules and extensions:

Modules

Modules allow you to shape the product according to your needs. Each module has a clearly defined scope ranging from tools for Web Development and Scripting, through a Public Cloud, all the way to the SUSE Package Hub, offering community-managed packages.

Modules enable you to provide only the set of packages required for the machine's purpose, making the system lean, fast, and more secure. This modular approach also makes it easy to provide tailor-made images for container and cloud environments.

Modules can be added or removed at any time during the lifecycle of the system. This allows you to easily adjust the system to changing requirements.

Modules are part of your SUSE Linux Enterprise Desktop subscription and therefore free of charge. They differ from the base of SUSE Linux Enterprise Desktop only by their lifecycle.

Extensions

Extensions provide advanced capabilities for tasks such as live patching and high availability clustering to SUSE Linux Enterprise Desktop. They are offered as subscriptions and require a registration key that is liable for costs. Usually, extensions have their own release notes that are available from https://www.suse.com/releasenotes.

1.1 Support

L3 support is generally provided for packages except for SUSE Package Hub and third-party modules. To check the support level for a package, run zypper info PACKAGE.

Long-Term Service Pack Support (LTSS) is available for most modules and extensions. For more information, refer to https://www.suse.com/products/long-term-service-pack-support/.

Some modules and extensions also include Extended Service Pack Overlay Support (ESPOS), which gives you significantly more time to upgrade and/or skip a service pack completely.

For more information on support and lifecycles, refer to the SUSE Technical Support Policy and the Product Lifecycle Support Policies. For a complete list of lifecycle dates by product, refer to the Product Support Lifecycle page.

2 Modules and extensions for the SUSE Linux Enterprise product family

The following modules and extensions are available within the SUSE Linux Enterprise product family:

Please note that the availability depends on the product. Not all modules and extensions are available for all products. Some modules are included in one product but also available as extension for another.

2.1 Basesystem

This module adds a basic system on top of the Installer. It is required by all other modules and extensions. The scope of an installation that only contains the base system is comparable to the minimal system installation pattern of previous SUSE Linux Enterprise Desktop versions. This module is selected for installation by default and should not be deselected.

  • Dependencies: None

  • Availability: Default on all products

  • Lifecycle: 10 years

  • Extended Support: 3 years LTSS

  • Support level: L3

2.2 Certifications

This module contains the FIPS certification packages.

  • Depends on: Basesystem

  • Available for: SLES, SLED, SLES for SAP, SUSE Linux Enterprise Real Time

  • Lifecycle: 10 years

  • Extended support: 3 years LTSS

  • Support level: L3

2.3 Desktop Applications

This module adds a graphical user interface (Wayland) and essential desktop applications to the system. This module is selected for installation by default; deselecting it is not recommended.

  • Dependencies: Basesystem

  • Availability: SLES, SLED (default), SLE WE (default), SLES for SAP, SLE RT (default)

  • Lifecycle: 10 years

  • Extended support: 3 years LTSS

  • Level: L3

2.4 Development Tools

This module contains compilers (including gcc) and libraries required for compiling and debugging applications. Replaces the former Software Development Kit (SDK).

Dependencies: Basesystem, Desktop Applications

  • Availability: SLES, SLES for SAP, SLED, SLE RT (default)

  • Lifecycle: 10 years

  • Extended support: 3 years LTSS

  • Level: L3

2.5 Python 3

This module provides two additional Python interpreters:

  • Python 3.11 and many additional maintained Python 3.11 modules. The Python 3.11 interpreter and modules are supported until the end of December 2027 and might be updated with the next service pack (if compatible and when needed).

  • Python 3.12 with all necessary modules for getting Python modules from PyPI. The Python 3.12 interpreter and modules are supported for 1.5 years until general support for SLE 15 SP6 ends.

Packages from the Python 3 module can be installed alongside existing Python packages, and they can coexist in the same system without impacting Python 3.6 workloads.

  • Dependencies: Basesystem

  • Availability: SLES (default), SLES for SAP, SLED (default)

  • Lifecycle: Python 3.11: 31 Dec 2027, Python 3.12: 1.5 years (end of SLE 15 SP6 general support)

  • Extended support: None

  • Level: L3

2.6 SUSE Package Hub

This module provides access to packages for SUSE Linux Enterprise Desktop maintained by the openSUSE community. These packages are delivered without L3 support but do not interfere with the supportability of SUSE Linux Enterprise Desktop. For more information, refer to https://packagehub.suse.com/.

  • Dependencies: Basesystem

  • Availability: SLES, SLES for SAP, SLE RT SLED

  • Lifecycle: None

  • Extended support: None

  • Level: None

2.7 Workstation Extension

This extension offers additional desktop applications and libraries. It is installed by default on SUSE Linux Enterprise Desktop. Adding the Workstation Extension to a SUSE Linux Enterprise Server installation allows you to seamlessly combine both products to create a fully featured server workstation. For more information, refer to https://www.suse.com/products/workstation-extension.

Warning
Warning: Unsupported kernel modules

The Workstation Extension installs the kernel-default-extra package, which includes additional kernel modules for desktop usage and enables loading of unsupported modules. If actually loaded, these modules may compromise your SLE support status.

Please evaluate if your hardware really requires additional kernel modules, and if so, test this expanded driver set in addition to the default set from the kernel-default package for possible configuration conflicts.

To prevent installation of the kernel-default-extra package, run zypper addlock kernel-default-extra.

  • Dependencies: Basesystem, Desktop

  • Availability: SLES, SLED (default), SLES for SAP

  • Lifecycle: 10 years

  • Extended support: None

  • Level: mixed L2/L3 (depending on package)

3 Installing and managing modules and extensions

Modules and extensions can be installed when initially setting up the system and on an existing SUSE Linux Enterprise Desktop installation.

3.1 Installing modules and extensions during system installation

Modules and extensions can easily be installed when setting up the system. The respective steps are part of the installation routine. Following the default installation path, this requires network access to contact the SUSE Customer Center or a local registration server (SUSE Manager or Repository Mirroring Tool), which provide the respective repositories. Offline installation is supported, too. In that case, an additional installation media is required. For detailed information, refer to Section 5.7, “Extension and module selection”.

3.2 Installing modules and extensions with YaST

To install modules & extensions from the running system, you need to make sure your system is registered with the SUSE Customer Center or a local registration server. If you have not done so during the installation, refer to Section 6.2, “Registering from the installed system” for instructions.

Tip
Tip: SUSE Linux Enterprise Desktop

As of SUSE Linux Enterprise 12, SUSE Linux Enterprise Desktop is not only available as a separate product, but also as a Workstation Extension for SUSE Linux Enterprise Server. If you register at the SUSE Customer Center, the Workstation Extension can be selected for installation. Note that installing it requires a valid registration key.

Note
Note: Viewing already installed add-ons

To view already installed add-ons, start YaST and select Software › Add-Ons.

Procedure 1: Installing add-ons and extensions from online channels with YaST
  1. Start YaST and select Software › System Extensions. YaST connects to the registration server and displays a list of Available Extensions and Modules.

    Extension and Module Selection dialog
    Note
    Note: Available extensions and modules

    The number of available extensions and modules depends on the registration server. A local registration server may only offer update repositories and no additional extensions.

  2. Click an entry to see its description.

  3. To add modules or extensions, select all components you want to install. Note that all extensions require additional registration codes which are liable for cost.

  4. Click Next to proceed.

  5. Depending on the repositories to be added for the extension or module, you may be prompted to import the repository's GPG key or asked to agree to a license.

  6. The YaST package manager opens to install release-packages for each module and, depending on your choice of modules and extensions, additional packages. It is strongly recommended not to deselect any of the preselected packages; you may, however, add additional packages.

    Choose Accept and Finish to conclude the process.

  7. If needed, adjust the repository Properties as described in Section 8.4.2, “Managing repository properties”.

Tip
Tip: Module dependencies

Similar to software packages, which may depend on other packages to function, a module may have dependencies on other modules. If this is the case, the modules on which it depends are automatically selected for installation.

3.3 Installing extensions and third-party add-on products from media

When installing an extension or add-on product from media, you can select various types of product media, like DVD/CD, removable mass storage devices (such as flash disks), or a local directory or ISO image. The media can also be provided by a network server, for example, via HTTP, FTP, NFS, or Samba.

  1. Start YaST and select Software › Add-On Products. Alternatively, start the YaST Add-On Products module from the command line with sudo yast2 add-on.

    The dialog will show an overview of already installed add-on products, modules and extensions.

    Installed Add-On Products dialog
  2. Click Add to install a new add-on product.

  3. In the Add-On Product dialog, select the option that matches the type of medium from which you want to install:

    Add-On Product dialog
    • To scan your network for installation servers announcing their services via SLP, select Scan Using SLP and click Next.

    • To add a repository from a removable medium, choose the relevant option and insert the medium or connect the USB device to the machine, respectively. Click Next to start the installation.

    • For most media types, you will be prompted to specify the path (or URL) to the media after selecting the respective option and clicking Next. Specifying a Repository Name is optional. If none is specified, YaST will use the product name or the URL as the repository name.

    The option Download Repository Description Files is activated by default. If you deactivate the option, YaST will automatically download the files later, if needed.

  4. Depending on the repository you have added, you may be prompted to import the repository's GPG key or asked to agree to a license.

    After confirming these messages, YaST will download and parse the metadata. It will add the repository to the list of Configured Repositories.

  5. If needed, adjust the repository Properties as described in Section 8.4.2, “Managing repository properties”.

  6. Confirm your changes with OK to close the configuration dialog.

  7. After having successfully added the repository for the add-on media, the software manager starts, and you can install packages. For details, refer to Chapter 8, Installing or removing software.

3.4 Deleting modules and extensions with YaST

  1. Start YaST › Software › Add-On Products.

    Installed Add-on Products dialog
  2. Choose the module or extension that should be removed and click Delete. Confirm the warning saying that all packages from the selected component will be removed.

  3. The YaST Software Manager opens and lists all installed packages from the deleted module or extension. Click Accept to remove all of them. It is strongly recommended to do so, because you will no longer get updates for packages from deleted modules or extensions. If you keep packages, make sure to at least remove the *-release package for each module or extension that gets deleted.

    Proceed with Accept and then OK.

Warning
Warning: Deleting modules

Note that you should never delete the Basesystem Module. It is also not recommended to delete the SUSE Linux Enterprise Workstation Extension and Desktop Applications Module.

Warning
Warning: No updates for packages from deleted modules and extensions

If you choose to keep packages from deleted modules or extensions, you will no longer receive updates for these packages. Because this includes security fixes, keeping such packages may introduce a security risk to your system.

3.5 Adding or deleting modules and extensions with SUSEConnect

  1. Run SUSEConnect --list-extensions to get an overview of available extensions:

    > sudo SUSEConnect -list-extensions
    AVAILABLE EXTENSIONS AND MODULES
    
        Basesystem Module 15 SP6 x86_64 (Activated)
        Deactivate with: SUSEConnect -d -p sle-module-basesystem/15.6/x86_64
    
            Desktop Applications Module 15 SP6 x86_64 (Activated)
            Deactivate with: SUSEConnect -d -p sle-module-desktop-applications/15.6/x86_64
    
                Development Tools Module 15 SP6 x86_64
                Activate with: SUSEConnect    -p sle-module-development-tools/15.6/x86_64
    
                SUSE Linux Enterprise Workstation Extension 15 SP6 x86_64 (Activated)
                Deactivate with: SUSEConnect -d -p sle-we/15.6/x86_64
    
            Python 3 Module 15 SP6 x86_64
            Activate with: SUSEConnect -p sle-module-python3/15.6/x86_64
    
            SUSE Package Hub 15 SP6 x86_64
            Activate with: SUSEConnect    -p PackageHub/15.6/x86_64
    
        Certifications Module 15 SP6 x86_64
        Activate with: SUSEConnect -p sle-module-certifications/15.6/x86_64
    
    
    REMARKS
    
    (Not available) The module/extension is not enabled on your RMT/SMT
    (Activated)     The module/extension is activated on your system
    
    MORE INFORMATION
    
    You can find more information about available modules here:
    https://www.suse.com/documentation/sles-15/singlehtml/art_modules/art_modules.html
  2. Run the commands in the listing for activating/deactivating a module or extension to add or delete a component. Note that adding an extension requires additional registration codes which are liable for cost.

Warning
Warning: Deleting modules

Note that you should never delete the Basesystem Module. It is also not recommended to delete the SUSE Linux Enterprise Workstation Extensionand Desktop Applications Module.

Important
Important: No automatic installation or removal of packages

SUSEConnect only adds or removes modules and extensions. It registers or deregisters the components and enables or disables their repositories, but it does not install or remove any packages. If you want this to be done automatically, use YaST to manage modules and extensions.

When adding a module or extension, SUSEConnect does not install default packages or patterns. To do this manually, use Zypper or YaST › Software Management.

When deleting a module or extension, SUSEConnect does not perform a cleanup. Packages from the module or extension remain installed on the system, but are no longer updated from a repository. To list these orphaned packages, run zypper packages --orphaned. To remove one or more packages, run zypper remove PACKAGE [ANOTHER_PACKAGE]. Alternatively, use YaST › Software Management and then View › Package Classification › Orphaned Packages to list and delete orphaned packages.

Warning
Warning: No updates for packages from deleted modules and extensions

If you choose to keep packages from deleted modules or extensions, you will no longer receive updates for these packages. Because this includes security fixes, keeping such packages may introduce a security risk to your system.

4 Module membership of packages

By default, tools for searching software packages (YaST Software Management or zypper search) are restricted to searching within active repositories. For an extended search including not yet activated remote repositories, you can run

zypper search-packages PACKAGE
Tip
Tip: Searching for packages in the SUSE Customer Center

You can also search for packages and their respective modules in the SUSE Customer Center Web interface at https://scc.suse.com/packages. A SUSE login is not required for this service.

To refine the search results, zypper search-packages offers the following options:

-x, --match-exact

Searches for exact matches.

-g, --group-by-module

Groups the search results by modules rather than by package name.

-d, --details

Additionally lists version numbers and repositories containing the package.

--xmlout

Generates XML output.

Below are a few examples of how to use zypper search-packages.

Example 1: Simple search

The following command searches for the packages nodejs and hawk. The first one is available in the Web and Scripting module, while the second one is part of SUSE Linux Enterprise High Availability. Both packages are not yet installed:

> zypper search-packages openjdk nodejs
Following packages were found in following modules:

Package          Module or Repository
                    SUSEConnect Activation Command
--------------- ----------------------------------------------------------------
------------------ -------------------------------------------------------------
java-11-openjdk  Basesystem Module (sle-module-basesystem/15.4/x86_64)
                    SUSEConnect --product sle-module-basesystem/15.4/x86_64
java-17-openjdk  Basesystem Module (sle-module-basesystem/15.4/x86_64)
                    SUSEConnect --product sle-module-basesystem/15.4/x86_64
nodejs14         Web and Scripting Module (sle-module-web-scripting/15.4/x86_64)
                    SUSEConnect --product sle-module-web-scripting/15.4/x86_64
nodejs16         Web and Scripting Module (sle-module-web-scripting/15.4/x86_64)
                    SUSEConnect --product sle-module-web-scripting/15.4/x86_64
[...]
Example 2: Searching for exact matches

If you know the exact package names, you can narrow the results down to exact matches by using the option -x:

> zypper search-packages -x java-11-openjdk nodejs14
Following packages were found in following modules:

Package          Module or Repository
                   SUSEConnect Activation Command
--------------- ----------------------------------------------------------------
------------------ -------------------------------------------------------------
java-11-openjdk  Basesystem Module (sle-module-basesystem/15.4/x86_64)
                   SUSEConnect --product sle-module-basesystem/15.4/x86_64
nodejs14         Web and Scripting Module (sle-module-web-scripting/15.4/x86_64)
                   SUSEConnect --product sle-module-web-scripting/15.4/x86_64
[...]
Example 3: Searching for packages that are already installed or available

If you search for packages that are already installed or are available in one of the modules that are available on your system, the search results differ. In the following example, the package vim is already installed. The package emacs is not installed, but is available for installation without having to add a module.

> zypper search-packages -x vim
Following packages were found in following modules:

Package  Module or Repository
           SUSEConnect Activation Command
--- -------------------------------------------------------------------------------------
---------- ------------------------------------------------------------------------------
vim Basesystem Module (sle-module-basesystem/15.4/x86_64)
      SUSEConnect --product sle-module-basesystem/15.4/x86_64
vim Installed
vim Available in repo Basesystem_Module_15_SP4_x86_64:SLE-Module-Basesystem15-SP4-Pool
vim Available in repo Basesystem_Module_15_SP4_x86_64:SLE-Module-Basesystem15-SP4-Updates

> zypper search-packages -x emacs
Following packages were found in following modules:

Package Module or Repository
          SUSEConnect Activation Command
----- ----------------------------------------------------------------------------------
--------- ------------------------------------------------------------------------------
emacs Basesystem Module (sle-module-basesystem/15.4/x86_64)
        SUSEConnect --product sle-module-basesystem/15.4/x86_64
emacs Available in repo Basesystem_Module_15_SP4_x86_64:SLE-Module-Basesystem15-SP4-Pool

Instead of searching for packages, you can also view the list of packages that belong to a module or extension. Start the YaST Software Management module and click View › Services. Select an entry to display the list of packages that belong to this module or extension.

5 Información legal

Copyright © 2006 – 2024 SUSE LLC y colaboradores. Reservados todos los derechos.

Está permitido copiar, distribuir y modificar este documento según los términos de la licencia de documentación gratuita GNU, versión 1.2 o (según su criterio) versión 1.3. Esta información de copyright y licencia deberán permanecer inalterados. En la sección titulada GNU Free Documentation License (Licencia de documentación gratuita GNU) se incluye una copia de la versión 1.2 de la licencia.

Para obtener información sobre las marcas comerciales de SUSE, consulte https://www.suse.com/company/legal/. Todas las marcas comerciales de otros fabricantes son propiedad de sus respectivas empresas. Los símbolos de marcas comerciales (®, ™, etc.) indican marcas comerciales de SUSE y sus afiliados. Los asteriscos (*) indican marcas comerciales de otros fabricantes.

Toda la información recogida en esta publicación se ha compilado prestando toda la atención posible al más mínimo detalle. Sin embargo, esto no garantiza una precisión total. Ni SUSE LLC, ni sus filiales, ni los autores o traductores serán responsables de los posibles errores o las consecuencias que de ellos pudieran derivarse.

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  11. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.

  12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.

  13. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version.

  14. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.

  15. Preserve any Warranty Disclaimers.

If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.

You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements".

You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See https://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

Copyright (c) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
A copy of the license is included in the section entitled “GNU
Free Documentation License”.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:

with the Invariant Sections being LIST THEIR TITLES, with the
Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.