using 2015 toyota prius c interior trim clips

Was just putting back the bottom-of-windshield plastic trim (on third gen hatchback); it has that style of fastener at each corner. What you said.

When the central button is flush, the jaws are splayed out, locking it in the hole. With the central button pushed in OR raised, the jaws are relaxed inward, allowing it to be removed.

 

Happened to me the first time I cleaned the HV battery fan, the manual says how to open them but it's not clear how to put them back

 

Here’s a pic of the centre shaft; the ridge/groove at the midpoint is where the jaws’ contact when the shaft’s cap is flush with the jaws’ cap. Either side the shaft diameter reduces.