Pull out front license plugs?

[MAC]

How do you pull out or unscrew or snap off the front license plate plugs on the front metal bumper?

It assumed it would be a piece of cake, but just spent 1 hour on them without success. Do I pull it straight out? snap off the round top and keep the stub inside for screws? or do I unscrew those 2 black plastic things plugging the 2 holes up front?

Cannot see what is behind the bumper and hard to grab on to the round black top/cover, tried using a flat screwdriver but must be very carefull not to scratch the black metal bumper. There must a very simple snappy way. Your assistance and advise are appreciated.