Did anyone actually anwer the original question?

Yes. It's a part designation. It doesn't have to mean anything, and
apparently it doesn't, thought it seems to be in the same family as
the part designation for other connectors that have some similarities.

Like the popular IC, the 5534. What does that mean?

But "XLR" looks as if it might be an initialization. 5534 doesn't and isn't.