About [[Wikimedia:Wlmmobile-failure-upload-token-heading/en]]

A "token" is an internal string that is used for communication, security, identification etc. See the English Wikipedia articles Security token.

Can/should we FAQ or glossary this?

The string description was already modified and already gives a better idea of the context.

Well, the point is, this is a recurring question, thus "token" with its at least two meanings could possibly be explained in a somewhat generalized way as an aid for the new translators.