This is the off bottom of the window that slides into the cam in the track. This piece broke off and the remainder is in the window. It looks similar to a 3" one you have posted but the "T" portion is not slanted like the one shown.
This is off a Discount Building Supply MASTDH 23 3/4 x 37 1/2 white window.
On the label there is the code:
LA: 7 G1: 13 G1:14