multiple taps at main

[Jerome W. Young]

this looks like it was made for two feeders but not three?

[Jerry Peck]

Made for parallel conductor sets, and, you are correct, one side of each is multiple tapped (and it does not look like it is made for that).

If ... that big *IF* ... if you could have removed those conductors and that lug, you would have been able to see on the lug what it was rated for. It might also state in the wiring diagram or on the label.

[Rick Hurst]

How about this one, Jerry?

[Jerry Peck]

How about this one

Rick,

That's commonly referred to as a 'AFU' type connection, typically done by WTFDIK 'electricians'. :)