Bogus label usage languages are recorded at least on commons, as the following query shows:
MariaDB [commonswiki_p]> SELECT COUNT(*) AS No, eu_aspect FROM wbc_entity_usage WHERE eu_aspect LIKE 'L.%' GROUP BY eu_aspect; +---------+--------------------+ | No | eu_aspect | +---------+--------------------+ … | 36 | L.de translate | … | 60 | L.itwikimedia | … | 2712 | L.⧼lang⧽ | | 2975 | L.⧼lang⧽ | +---------+--------------------+ 145 rows in set (2 min 20.97 sec)
This probably only affects multilingual wikis. T173196: Client term access in user language should track all labels/ descriptions as being used on multilingual wikis will surely solve this as a side-effect.