How are y’all?
I just learnt that UCs do not require letters of recommendation but some specific campuses and/or majors do. What are those campuses/majors?
Thanks
UC Berkeley is the only UC that asks for Letters of Recommendation by invitation only as of 2019. This could change for 2020 but mostly likely not. Once you submit your UC application, you will be notified by UCB if they want you to submit LOR’s. Not specific for any majors at UCB.
I know this is a pretty basic, maybe meaningless, question but is it a good thing or a bad thing if UCB asks for rec? 
In my experience, it is UCB and it is by invitation only.
After submitting your application, some students receive the invitation and instructions. My S 2014 received the invite — 4.0, w 4.3, 34 ACT. Other S 2016 no invite — 3.88, w 4.2, 35 ACT. Both accepted to L&S.
My opinion is that is a good thing since they want to learn more about you through the LOR’s. There are plenty of examples of applicants that submitted LOR’s and were accepted and plenty of examples of applicants that submitted LOR’s and were not accepted. Only a small fraction of applicants around 12-13% will receive the request.
For my S that received the invite it was just a few days after he submitted. He also submitted very close to end of cycle. Maybe just a day or two before final deadline.
It’s a good thing - it means they’re interested and want to know more about you.