The app's privacy notice, effective October 7, states it in one line: "If you used face recognition before this version, it stays on for you."
Until that build the app's face recognition preference was declared with a default of true.
An install where onboarding was completed before this build, or where at least one face is already enrolled, has recognition switched on and written down as a stored value.
A fresh install is seeded off, in the file's words, "so a later default change cannot flip it".
Avenkin is not Meta software, and Meta ships no face recognition on these frames.