Little plastic things that secure access panels

fasteners, I believe

 

I call them pushpins.

To remove them, take a small flat blade screwdriver and pull up on the middle tab to release the center pin, and then remove the outer fingers from the hole. There are slots in the top piece for inserting the screwdriver.

To install, with the center pin retracted, insert the outer fingers into the hole and then push the pin to lock in place.

 

Harbor Freight sells a tool for this exact job.
Push Pin Pliers

 

It has taken me a while to learn to take this things out without annoyance.

Tools
A phillips screwdriver
A flat screwdriver

1. Use the Phillips to unscrew and raise the middle pin. If the entire fastener turns, I apply a little pressure to the outer head of the fastener with the flat screwdriver.

2. When the middle pin is raised a bit, I insert the flat screwdriver in the gap and pop the fastener up.

Like many things, really easy once you get the hang of it.

p.s., these fasteners are made of really cheap plastic that turns brittle in no time flat. I bought of bag of them for a couple of dollars on Ebay and now don't care if one breaks.

 

The Repair Manual refers to them as clips. It also shows the correct removal/installation instructions.
They are made of plastic so even if you followed the instructions, they can still be damaged after many removal/installation, just replace with new ones accordingly.

Vincent