Some data from the inside:

Reality Labs (AR/VR) hit less hard than the rest of the company. No one on my team or adjacent teams let go.

Most bootcampers (unallocated new hires) are gone, even ones that were performing well.

Low performer from my past team outside RL was let go, so it appears performance was a factor for a lot of roles, rather than just axing entire teams based on business need.

edit: updated to clear up some confusion about the meaning of RL and bootcampers