What is Hahog Feature dectors in OpenSfm?

I was looking into the different feature detectors/ descriptors for OpenSfm. I saw that there is Hahog but I couldn’t tell what this was. I looked at the source code and it appears to call Sift in it a couple of times. Also, I saw somewhere that it was recommended to try using Hahog instead of Sift because they get the same results.

Does this mean Hahog is actually based on Sift? If not, what type of license is Hahog released under (presumably BSD)?

HAHOG is the name OpenSfM uses for the combination of Hessian Affine feature point detector + HOG descriptor. The HOG descriptor is the same as used in SIFT, the detector is different.
The code in OpenSfM for this is BSD licensed.