Help identifying bolt from 991.2 c2s

[Benelux]

Whilst cleaning my car I found a 30mm long 8mm bolt with captive washer, sticking out loose from the edge of the rear undertray. Can anyone identify what it may be from. It was on top of the rear floor undertray inboard of the passenger side rear wheel to the front of the metal cross member that runs between the rear suspension. I attach a couple of photos. The bolt head fits a 13mm socket.
The yellow arrow in photo indicates appropriate where bolt was wedged sticking out.

Edited by Benelux on Thursday 18th May 09:09

[Benelux]

Photo of bolt

[STiG911]

Looks very similar to bolts that hold up the under trays or plastic air ducting.
Not suspension related as those are all much bigger or Hex / Torx heads.