Due to incorrect release info, Debian appstream produces no release
information as shown below:

Releases:
- version: '44.0'
  type: stable
  unix-timestamp: 1679184000
- version: '43.0'
  type: stable
  unix-timestamp: 1663459200
- version: 43~rc
  type: development
  unix-timestamp: 1662163200
- version: 43~beta
  type: development
  unix-timestamp: 1659830400

This causes GNOME Software to display empty or less useful
information. Fixed with the following command:

$ appstreamcli validate org.gnome.Characters.appdata.xml

Refer: https://appstream.debian.org/sid/main/issues/gnome-characters.html.
Refer: gnome-software#2251