What is this Hex Screw that was left behind?

[Ch0wd3r]

Just had oil change recently and also passenger side taillight assembly replaced under warranty at dealership. Being a few days and just found this (photos attached) hex screw that was left behind on passenger seat floor. It has the letters ATC (I think) and 8.8 (grade i think), and measured it to be either M5 or M6 (think its m5 but too close to tell exact) and 25mm long.

Anybody with service manual know where this belong too? Hoping it's not a critical screw for mechanical systems but panels/bumper. Certainly doesn't make me feel at ease knowing something wasn't put back....

Thanks in advance!

 

[cryptovince]

Sorry that I can't provide an answer but, I just wanted to chime in that I've had a washer without a screw/bolt fall from my driver's side of the dash onto the floormat, and that puzzled me as well.

 

[nimbusblack]

sump plug /s