This boar has rubs like this many places on this property,like deer
He rarely uses the feeders for food, his sows and off spring do
Or is he sharping his cutters
Not sharpening his cutters, that is accomplished daily as the 'cutter' rubs against the 'whetter' in the upper jaw.
I don't know if there is an accepted 'term' for the markings left....but I can them 'cuttings'.
Most folks would not make the distinction between it (a cutting) and a 'rub' left by a Buck deer, but if you look closely it is easy to tell.
Cuttings are made by Boars fairly often, usually in an area they inhabit with some frequency. It would seem to be some type of 'call sign' for other hogs, not necessarily territorial in nature. If you find a fresh one, it will have not only the visual 'cut marks' from the tushes, but also saliva.
The best time to find these (and KNOW what it is), is between February and August, when the Buck Deer are either without antlers or do not have a hardened antler (and thus not rubbing). NO mistaking a fresh cutting that way.
Here is an example of what you might find, it will always be on a small sapling and will not be marked heavily (as a Buck rub would be).

Look closely and you will be able to see the distinct raking marks made from the cutters or from where they actually grab/mouth the tree.

In my area (Deep East Texas) they seem to show a preference for trees that ooze sap when scored (Pine, Cypress and Osage Orange) but will mark anything.
Any time I find more than a few of these cuttings, I will look for evidence of a bedding area. Boars will clear off small spots to lay in.

Good to know where they are hanging out, but as you can imagine...by the time you've walked through his bedroom, you've pretty much ruined the area.