These are headlight housing covers off of a 2000 VW Passat (cover the wiring/plugs in the engine bay). Smaller one from the high-beam (inner) side, large from low-beam (outer) side.
The smaller one fits inside the hole.
Larger one fits on the outside of the hole.
Both fit loose, but will keep water & junk out under normal driving conditions.
If you powerwash the engine, they will blow off unless secured (with silicone?).