aegisub.appdata.xml cannot pass validation

[0tkl]

Currently the AppImage build can finish because of this warning:

WARNING: appstreamcli command is missing, please install it if you want to use AppStream metadata

After apt-get install appstream on Ubuntu 22.04, or switch to Ubuntu 24.04:

……
AppStream upstream metadata found in usr/share/metainfo/aegisub.appdata.xml
/home/runner/work/Aegisub/Aegisub/appimage/appdir should be packaged as Aegisub-x86_64.AppImage
Trying to validate AppStream information with the appstreamcli tool
In case of issues, please refer to https://github.com/ximion/appstream
aegisub.appdata.xml
  W: aegisub.desktop:3: cid-desktopapp-is-not-rdns aegisub.desktop
  I: aegisub.desktop:65: nonstandard-gnome-extension kudos
  I: aegisub.desktop:87: developer-name-tag-deprecated
  I: aegisub.desktop:~: developer-info-missing

✘ Validation failed: warnings: 1, infos: 3
Failed to validate AppStream information with appstreamcli
run_external: subprocess exited with status 3

[sosie-js]

In fact we cannot use the same id org.aegisub.Aegisub as an application under aegisub exists already in flathub so it need to be renamed into org.archit3cht.aegisub

something.AppDir
  |__AppRun
  |__org.archit3cht.aegisub.desktop (symlink from usr/share/applications)
  |__aegisub.png 
  |__usr
      |__share
           |__metainfo
                |__org.archit3cht.aegisub.appdata.xml
           |__applications
                 |__org.archit3cht.aegisub.desktop

Essentially, the org.archit3cht.aegisub.appdata.desktop ought to be placed in the folder something.AppDir/usr/share/applications.
Then symlink this file into the something.AppDir folder as described in AppImage documentation.

Thus the file aegisub.appdata.xml have to be renamed into org.archit3cht.aegisub.appdata.xml with valid content that makes appstream's flatpak happy)