To mail you documents related/associated with your employment? Not really unheard of to receive 401k/insurance/other benefits mail. Also, taxes and tax documents like W2’s
Potentially background checks? Maybe? Otherwise yeah it’s a bit weird and more information than they really need.
Overreach in data collection is everywhere these days sadly… far too many things are not properly considered PII (personally identifiable information) even though multiple things in aggregate could completely doxx a person.
It’s really more of a US usage tbh. Most civilized countries have actual pensions and retirement plans (or at least I hope they do, not for lack of attempts to remove them)
Everyone and their mother in entry level job postings I can remember (2016-2020 ish range, so may have changed) had a caveat of passing a background check. This being in a relatively wealthy suburb, too. I imagine there’s some sizeable kickbacks from the companies doing them.