GNOME Software is in an unusual position in a distribution, as it lies at the interface of the GNOME project and the distribution’s packaging and release infrastructure. GNOME Software is the user interface which a lot of users will use to see updates and new releases from their distribution. Distributions understandably want to be able to put some of their own branding on this interface, both to publicise their distribution and to confer some level of official authority on the updates being provided.
For this reason, GNOME Software has a few ways which vendors can use to customise its appearance.
A variety of different customisations have been implemented in the past, some of which have been removed and others are still present. This document aims to document the ones which are still present and supported. This document is not necessarily complete. It will be added to over time as different customisations are refreshed and updated.
If there is a supported customisation method which is not in this document, please submit a merge request to document it.
Likewise, if your distribution would like to customise GNOME Software in a way which isn’t currently supported, please open a new issue to discuss it. We don’t guarantee to implement anything, and customisations are limited to adding branding in specific areas.
The principles which guide vendor customisation features in GNOME Software are:
| Principle | Rationale |
|---|---|
| Avoid requiring vendor specific code | Otherwise vendors have to maintain and test GNOME Software plugins, which is a lot of work. |
| Don’t use GSettings unless customisations really should be per-user. | While GSettings overrides are convenient, they are designed for user preferences, not packaging customisation. |
| Don’t require downstream patching of GNOME Software, although configure-time arguments are OK. | Many distributions are derived from other ones and would not like to have to maintain a packaging fork in order to make small customisations. |
| Be mindful of release cadences. | If customisations related to a new OS version were tied to the release cycle of GNOME Software, a new GNOME Software packaging release would have to be done by a distribution in advance of making their new OS release, which is a burden. It’s easier to allow distributions to put customisations specific to a new OS version into a separate package. |
The background image which is shown when a new OS upgrade is available is
customisable in several ways. It’s displayed by the GsUpgradeBanner widget,
and shown on the Updates page. An example upgrade banner with
background image is shown below:
If your distribution has a specific GNOME Software plugin providing its upgrade
information, that plugin can provide CSS for rendering the background. See the
fedora-pkgdb-collections plugin for an example of this.
Otherwise, the background image is looked up from several well-known locations, in order:
${DATADIR}/gnome-software/backgrounds/${os_id}-${version}.png${DATADIR}/gnome-software/backgrounds/${os_id}.png
${DATADIR} is the configured data directory (typically /usr/share).
${os_id} is the ID= value from /etc/os-release, and ${version} is the
version string being upgraded to.
There are several ways to promote and highlight specific apps in GNOME
Software. On the Explore page, there’s a carousel of featured apps
(featured_carousel), and an “Editor’s Choice” section (box_curated). Both of
them highlight curated sets of apps. The same is true on each category
page: a carousel (top_carousel) and an “Editor’s Choice” section
(featured_flow_box) are present. Category page is the page shown
when one of the app categories (Create / Develop etc) in the
Explore page is clicked. This is explained in the following image:
Both pages also have a “New & Updated” section (box_recent or
recently_updated_flow_box) presented below “Editor’s Choice”. The apps
listed in the new and updated section are not curated: they are chosen as the
apps which have had a recent release, according to the
component/releases/release[@timestamp] attribute in their metainfo.
Technically these are the results of a GsPlugin.list_apps_async() query with
GsAppQuery:released-since set.
Apps are included in any of the curated sets through having special metadata in their metainfo. The required metadata is different for the different sections:
- Carousel on the Explore page: Apps are included if they have
component/custom/value[@key='GnomeSoftware::FeatureTile]orcomponent/custom/value[@key='GnomeSoftware::FeatureTile-css]set in their metainfo. They are also required to have a high-resolution icon, and the set of apps shown in the carousel is randomised and limited to (for example) 5. Technically these are the results of aGsPlugin.list_apps_async()query withGsAppQuery:is-featuredset. - “Editor’s Choice” on the Explore page: Apps are included if they
have
component/kudos/kudo[text()='GnomeSoftware::popular']set in their metainfo. Technically these are the results of aGsPlugin.list_apps_async()query withGsAppQuery:is-curatedset. - Carousel on the category page: Apps are included if they are in the
Featuredsubcategory of the displayed category. They are also required to have a high-resolution icon, and the set of apps shown in the carousel is randomised and limited to (for example) 5. - “Editor’s Choice” on the category page: Apps are included if they meet the requirements for being in the carousel, but weren’t chosen as part of the randomisation process.
Example:
<?xml version="1.0" encoding="UTF-8"?>
<components>
<component merge="append">
<!-- The ID must always be present to allow merging -->
<id>org.gnome.Podcasts</id>
<!-- Make the app a candidate for inclusion in the carousel on the
Explore page (if it has a hi-res icon). -->
<custom>
<value key="GnomeSoftware::FeatureTile">True</value>
</custom>
</component>
<component merge="append">
<!-- The ID must always be present to allow merging -->
<id>org.gnome.Boxes</id>
<!-- Include the app in the “Editor’s Choice” section on the Explore page. -->
<kudos>
<kudo>GnomeSoftware::popular</kudo>
</kudos>
</component>
<component merge="append">
<!-- The ID must always be present to allow merging -->
<id>org.gnome.Builder</id>
<!-- Make the app a candidate for inclusion in the carousel or
“Editor’s Choice” section on category pages (if it has a hi-res icon). -->
<categories>
<category>Featured</category>
</categories>
</component>
<!-- more components -->
</components>There are several ways to modify the metainfo for apps so that they are highlighted as required, all of which involve providing an additional appstream file which sets the additional metainfo for those apps.
There are 3 main approaches to providing these additional appstream files:
In this approach, a distro-specific appstream file is installed in
${DATADIR}/swcatalog/xml via gnome-app-list package, providing and
updating it via normal distribution channels.
If distributions wants to promote a different set of apps (than the
one provided by gnome-app-list), the recommended way is to provide
the additional AppStream file in a separate distribution package
(for example, debian-app-list). If the distribution already ships
the gnome-app-list package, the distribution package should mark
gnome-app-list as ‘conflicting’ with the distribution-specific package,
so the two cannot be installed at the same time.
Distributions should not patch the app list provided by gnome-app-list,
as that app list has been curated and endorsed by GNOME. Alternative
lists of promoted apps should be labelled with their curator, not GNOME.
For distributions which can’t do regular updates of individual files – such as
image-based distributions – GNOME Software can download distro-specific
appstream files from the internet. List them in the external-appstream-urls
GSetting in /org/gnome/software, typically via a distribution-provided
GSettings override. Each URL must be HTTPS, and must point to a valid appstream
file. GNOME Software must be configured with -Dexternal_appstream=true for
this to work.
GNOME Software will periodically check and download any updates to these
files, and will cache them locally. Ensure the If-Modified-Since HTTP header
functions correctly on your server, or GNOME Software’s caching will be
ineffective.
The external-appstream-urls mechanism may change in future.
GNOME Software ships a default list of featured apps, chosen to match
the GNOME Circle. See
data/assets/org.gnome.Software.Featured.xml for this list, and for an example
of the metainfo XML needed to feature or highlight apps. See
data/assets/org.gnome.Software.Curated.xml for a default hard-coded list of
curated high quality apps, which is displayed in the “Editor’s Choice”
section of the Explore page.
Since GNOME 47, gnome-app-list is the recommended way to ship the
additional appstream files. AppStream files shipped with GNOME
Software should be used as an interim solution until gnome-app-list
or your distribution provided app list package (as explained
above) is available in your distribution.
Pass -Ddefault_featured_apps=true when configuring GNOME Software to
enable the default list of featured apps. Pass
-Dhardcoded_curated=true to enable the default list of “Editor’s
Choice” apps. These options are enabled by default until GNOME 46, and
disabled by default from GNOME 47 onwards to actively discourage their
usage.
Deployments can feature their own apps, which will be shown in the Explore page in its own section. To have the section shown, two files need to be provided. The number of deployment-featured apps is limited in the UI, and if not enough deployment-featured apps are found, then the section will not be shown at all.
The first file is org.gnome.Software.DeploymentFeatured.xml, which works similarly
to org.gnome.Software.Featured.xml and should be saved beside it in an appstream
directory. It sets the GnomeSoftware::DeploymentFeatured key on apps which should
be featured for this distribution or deployment. The value of this key is a string
containing the deployment name as an identifier.
The second file is deployment-featured.ini, which contains a human-readable title and
the selector for the section. The title is a localized key, and is used to set the heading
for the section on the Explore page. When the title is not provided, a fallback title
"Available for ${distro-name}" is used. The selector defines which apps should be picked.
It is a semicolon-separated list of GnomeSoftware::DeploymentFeatured key values, thus
the deployment can feature apps from zero or more vendors.
The deployment-featured.ini file should be saved in one of the sysconfdir, system
config dirs or system data dirs. They are checked, in that order, for existence of
the gnome-software/deployment-featured.ini file. The first directory containing
it will be used. The relevant file names are /etc/xdg/gnome-software/deployment-featured.ini,
/usr/local/share/gnome-software/deployment-featured.ini and
/usr/share/gnome-software/deployment-featured.ini.
Any changes to these files, including adding or removing them, will only be noticed when GNOME Software is restarted.
Example files can be found in the contrib/ directory.