Top widow latch
See our 26-408 Tilt Latches. Look this pair over and see if you think they could work for you.
The 26-408 usually installs from the top and clicks in. If you look at the image below, you'll see how the hole looks when the tilt latch is out. The 26-408 has a kind of gap in the front that pinches around that strip of vinyl on the far right side. I'll also provide an image of that to show you what I mean.


The 26-408 "scoops" into that gap at an angle. In all honesty, I've never personally removed this latch myself (these things are usually broken by the time I see them), but I would imagine you would use a screwdriver to "unclick" it out of place and slide the back end out first. Let me know if that makes sense to you.