Last I recall they’re just a crappy 5 megapixel Arducam camera module based on teardowns.

https://www.cehrp.org/dissection-of-flock-safety-camera/

https://www.arducam.com/product/arducam-ov5647-noir-camera-b...

Lol that's almost literally the cheapest possible option. You can get these for $3-4 (on a board and with a mipi cable and everything) from China - I have a dozen in a box that I bought to test out a camera array idea before shelling out for nicer sensors.

The best part is seeing someone tear a Flock camera apart, see the camera, and immediately go slap it on their 3D printer and hook it into their Pi and just have it work out of the box ;)