Polo 2011 - Metal tab bottom of door?

[MLCNO18]

Collegue at work had a Polo as aloan car whilst his Passat was in for service, we were having a quick look round it when we left at night and noticed a slot in the sill (with a rubber/plastic boot in it), then looking under the bottom of the door panel there was a piece of flat steel stuck out with corners cut off and a hole towards the pointy end.

Any ideas what it's for - didn't seem to be anything in the sill that would locate into the hole on the steel tab.

We both keep forgetting to ask local dealers when we're in.

Can only presume it's to hang the door for painting and it's a pain to remove so easier to leave on and have hole in the sill????

Thanks

[Crasher]

Side impact door interlock tab. If the car gets hit in the side, it helps stop the door caving in.

[MLCNO18]

Thanks, couldn't feel anything in the sill to go through the hole and the boot had no holes in it either but could imagine it would help stop the door popping.