You’re giving me an idea. Given the small size of the update and the security level difference of just one day (5th vs. 6th November), I suspect it might be fixing a serious security issue that was talked about in this forum just a few days ago. From what I remember, the most recent FP2 update had fixed it (see the CVE-2021-1048 comment here), but according to @lucaweiss the most recent FP3 update (A.0132) did not include it. So maybe this is the left-over that still needed to be addressed ASAP.
P.S.: Sorry for the many edits I made to this reply, but I wanted to add the correct references 