Translation for locale with country code (pt_BR) is from the language without country code (pt)

[velsinki]

Over at GNOME Settings, someone reported https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/3252. I traced this back to what is most likely an AppStream issue.

Basically, we have an appdata.xml file (org.gnome.Settings.appdata.xml.zip) that has

  <name xml:lang="pt_BR">Configurações</name>
  <name xml:lang="pt">Definições</name>

But if I

LANG=pt_BR.UTF-8 appstreamcli dump org.gnome.Settings.desktop

I get

  <name>Definições</name>

instead. The description and developer name are also from pt instead of pt_BR. That doesn't seem correct to me.

Is there anything we are doing wrong, or is this an issue from here?