"Tab" got adopted by the new-ish tabloid student newspaper The Tab (nice double meaning) which since opened several franchises in other universities.

It's definitely used in other contexts. The main two that come to mind are the alumni email service (...@cantab.net) and the Cambridge MA (shortened to MA (Cantab.)).

I do occasionally hear it mispronounced as "Cantabridgarian".

There's a bar in Cambridge, MA called The Cantabridgian.

Also in the 80s there was a small computer company based in Cambridge, England called Jupiter Cantab. They made the Jupiter Ace computer, a semi-clone of the ZX81 with Forth in ROM instead of BASIC.

I am familiar with the Cantab Lounge, but not the Cantabridgian.

Cantab sure... I was talking about "Tab" specfically though.

They're all used primarily to refer to members of the universities, but at least occasionally they're used to refer to residents of the towns as well.