Comment # 4 on bug 1196701 from Stanislav Brabec

Sorry, no. Weblate cannot translate desktop files directly, as well as any
other multilingual resource files (e. g. ini/keyfiles files, multilingual xml
files like soundlists, screensaver descriptions etc.)

But intltool can do it, and in case of automake based projects, tools line
autopoint or intltoolize (maybe even new versions of gettextize) can help to
prepare the project.

Or you can prepare the infrastructure directly, as noted in the comment 3.

Basically, these tools extract strings from desktop files, split it per
language, and then put back translated strings.