Use placeholders for GNOME 3.xx (development) (stable) (old stable)
On https://l10n.gnome.org/languages/da/ i see strings with:
GNOME 3.xx (development)
GNOME 3.xx (stable)
GNOME 3.xx (old stable)
Click the + next the Archives to see more:
GNOME 3.26 (old stable)
GNOME 3.24 (gammel stabil)
GNOME 3.22 (gammel stabil)
GNOME 3.20 (gammel stabil)
GNOME 3.18 (gammel stabil)
GNOME 3.16 (gammel stabil)
GNOME 3.14 (gammel stabil)
GNOME 3.12 (gammel stabil)
It would seem each time the releases changes the strings are changed in the translations (pot/po files) and then it becomes a mixture of translated and untranslated strings if the strings are not translated each time they change.
So instead of translators having to update the strings each time the releases change i suggest using placeholders.
So instead of:
msgid "GNOME 3.32 (development)"
msgid "GNOME 3.30 (stable)"
msgid "GNOME 3.28 (old stable)"
Have:
msgid "GNOME %s (%s)"
msgid "development"
msgid "stable"
msgid "old stable"
That way translators only have to translate the strings one time.
Maybe add some comments to help the translators:
#. Translators: example "GNOME 3.xx (development)"
msgid "GNOME %s (%s)"
#. Translators: example "GNOME 3.xx (development)"
msgid "development"
#. Translators: example "GNOME 3.xx (stable)"
msgid "stable"
#. Translators: example "GNOME 3.xx (old stable)"
msgid "old stable"
The string "Extra GNOME Applications (stable)" could also use it.
#. Translators: example "Extra GNOME Applications (stable)"
msgid "Extra GNOME Applications (%s)"