Since they’re on a garage door opener, they’re probably designed to be very simple to operate. Not to malign electricians or general contractors, but they don’t have the time to deal with fussy mechanisms - they’ll deal with it once, then never use that brand again.

Since the hole is at an angle I’d guess they’re spring loaded but manually operated. That little slot on the top of the orange buttons looks designed for a flat screwdriver to push it down, opening the clamping mechanism, and it’s spring loaded to come back up and clamp the wire.

Also, looking at the shape of the body and orange parts, they can only move in/out.

Just my guess. Can you shine a light into the hole and see the mechanism at all?

Try pushing an orange piece in with a small screwdriver and little pressure.