In "write" functionality, new "sentence-variants" feature is enabled. On the other hand the variant names are not shown, only variant bcp-47 codes are shown, because the code tries to look them up from the .ftl (translation) files. As they are only intelligible for that language, the team correctly decided to put these names into the database (otherwise we would have a thousand terms for each locale to translate - without any use).

So, it should actually get the "translations" from the database, and should not try to use l10n/localization.

See:

As you might guess, bcp-47 codes are not very intelligible for an average user.