I'm unsure what user this is; the format is from before the real service groups (group id = 50943, but that group doesn't exist anymore).
I can't find the username p50380g50943 in any /data/project/*/*.cnf on tool labs, so either
* it's either a very old table that's not in use anymore, or
* it's being accessed using credentials stored elsewhere, or
* ~~another user has permissions on that database. ~~ (only p50380g50943 has access)
I'm not sure if there's any easy way to figure out who owns the table, other than grepping all of /data/project...