Good observation & I have thought the same thing - the attributes are often there and never removed by “Q”. The values can be anything, though - and I’ve often wondered why anons haven’t searched using those though most likely they are true points of origin (which is a possibly unintended exposure)
The info is only useful to the server and the receiver. Those of use "outside," looking at the transaction, can't make anything of it.
We could speculate on the fact that Q doesn't remove it. Lazy? Ignorant? Intentional dare to the server or those who can get access to server logs to "look him up"?