The message temp-user-banner-description is used as "lego": it is concatenated in run time with colon-separator and the account name.
It would be much better to put the account name into the message as a parameter, and to let the translators choose the punctuation. Currently, translating this is quite inconvenient to some languages.
In fact, it's not so great even in English: "You are using a temporary account: ~2025-41753".
It would make more sense to me without the colon and with "the" instead of "a", like this: "You are using the temporary account ~2025-41753".
There are a few similar messages in other contexts, and they should all be consistent.
