[gnome-software.wiki] Update Software metadata

[Philip Withnall <pwithnall src gnome org>]

commit ddbe5d7f0646264c548e94395e8396fd9e918dca
Author: Philip Withnall <philip tecnocode co uk>
Date:   Fri Mar 4 14:30:13 2022 +0000

    Update Software metadata

 Software-metadata.md | 54 +++++-----------------------------------------------
 1 file changed, 5 insertions(+), 49 deletions(-)
---
diff --git a/Software-metadata.md b/Software-metadata.md
index d8fcce8..0f5e63a 100644
--- a/Software-metadata.md
+++ b/Software-metadata.md
@@ -225,57 +225,13 @@ Colours should be chosen so that they:
  * Contrast with the foreground text colour in the Adwaita theme (`#2e3436`) and in its dark variant 
(`#eeeeec`). This generally means choosing a colour with a medium level of brightness.
  * Contrast can be checked using the [Contrast app](https://apps.gnome.org/app/org.gnome.design.Contrast/).
 
-At least one colour should be specified. More can be specified if one colour can’t satisfy all the 
requirements above, and GNOME Software will choose the most appropriate to use in the carousel tile.
+At least one colour should be specified. More can be specified if one colour can’t satisfy all the 
requirements above, and GNOME Software will choose the most appropriate to use in the carousel tile. If 
exactly one colour is specified, its brightness and saturation may be modified to improve contrast with the 
foreground colour. If more than one colour is specified, the one with the best contrast with the foreground 
colour will be chosen, and its brightness and saturation will not be modified.
 
 ### How to test carousel tile background colour changes
 
-On some distributions, you can test your changes by editing 
`/usr/share/app-info/xmls/org.gnome.Software.Featured.xml`. (On GNOME OS, run `sudo ostree admin unlock` to 
be able to temporarily edit this file.) Remove almost all the other apps – you need to leave 4, since 
Software has a minimum threshold – and add a section for your app, as follows:
-
-```xml
-<?xml version="1.0" encoding="UTF-8"?>
-<components>
-  <!-- The app I want to test -->
-  <component merge="append">
-    <id>org.freedesktop.Bustle</id>
-    <categories>
-      <category>Featured</category>
-    </categories>
-    <custom>
-      <value key="GnomeSoftware::FeatureTile">True</value>
-      <value key="GnomeSoftware::key-colors">[(20, 200, 235)]</value>
-    </custom>
-  </component>
-  <!-- Other apps to pad out the list -->
-  <component merge="append">
-    <id>org.gustavoperedo.FontDownloader</id>
-    <custom>
-      <value key="GnomeSoftware::FeatureTile">True</value>
-    </custom>
-  </component>
-  <component merge="append">
-    <id>re.sonny.Commit</id>
-    <custom>
-      <value key="GnomeSoftware::FeatureTile">True</value>
-    </custom>
-  </component>
-  <component merge="append">
-    <id>re.sonny.Junction</id>
-    <custom>
-      <value key="GnomeSoftware::FeatureTile">True</value>
-    </custom>
-  </component>
-  <component merge="append">
-    <id>re.sonny.Tangram</id>
-    <custom>
-      <value key="GnomeSoftware::FeatureTile">True</value>
-    </custom>
-  </component>
-</components>
+Modify the metainfo file for your application, and then run Software with:
+```sh
+gnome-software --show-metainfo=/path/to/app.metainfo.xml,icon=/path/to/app/icon.png
 ```
 
-Now restart gnome-software:
-
-```
-gnome-software --quit
-gnome-software
-```
\ No newline at end of file
+The details page for your application will be shown. If you navigate back to the overview page of Software, 
your application will be the only one in the ‘featured’ carousel.
\ No newline at end of file