L10n-bot does not export some Pywikibot translations
Fragment of a discussion from Support/LiquidThreads
Only special thing I see is that these are optional messages and the only ones in that language for that group.
There are others too but shipped years ago: https://gerrit.wikimedia.org/r/plugins/gitiles/pywikibot/i18n/+log/1625ccca46e697df922195a03f23e3461f0efc8c/interwiki/arz.json
This is resolved by Phab:T159122.