What going on with this manifold

Can anyone help me with this manifold? I don’t know what those marks are on the bottom. Unfortunately, at the time, I just snapped the photos. So I don’t have any more info, just the photos. If you can help me that would be great, thanks.

Looks like scars from a recip saw or rotary tool.

It looks like they covered it up, and the drywall finisher cut it with his zip bit.

Wow, I’m impressed. Thank you.