architecture of door column braces?

Miscellaneous and Personal Stuff I Must Share
1

I am curious about a minor detail I noticed is pictures of old European doors. I do not understand the purpose of the braces at the bottom of the door columns seen on some but not all of these images.

When present they seem to have some minor structural need, but they aren’t always there. Perhaps the clearest example is the 13th photo. I don’t see any decorative use for that case. It must be there for a functional reason.

Does anyone have any idea what they are and what purpose they serve?

2

My first thought is that they are to keep wheeled conveyances—more particularly, the projecting hubs—from striking the door frames. But I’m not sure what sorts of wheeled carts would be coming through these fancy front doors.

It’s also possible they’re vestigial, decorative emulations of iron braces used to ensure that wooden door frames remained orthogonal to the foundation.