A wild git hawser appears in my .gitconfig

Before I made a commit in my dotfiles repo I saw something weird that appeared in my .gitconfig.

[filter "hawser"]
clean = git hawser clean %f
smudge = git hawser smudge %f
required = true

Since life is too short to read all the wild stuff that randomly appears in my config files, I just added that modification to my commit. After some days, people started asking on my dotfiles repo where did those things appeared.

In a happy ending, somebody talked to Github's support and those lines are added by Github for Mac.

Problem solved!

But I still don't know what hawser means...