I've read through the standard comment of barrymead that there's a white cat in the pyramid, but I haven't found it (unless it doesn't work right now due to the engine updates?).

My best guess was to go through the passage to the right of the stairs at the entrance (which you need to open the path with an hidden switch), follow it to outside, then go inside the hole after the jump, but I haven't seen it yet.

I'm doing a let's play of this mod and I wish to show everything that's possible.