If it's the first time you check-out a repo you need to use --init first:
git submodule update --init --recursive
my ttf fonts
copy the fonts to ~/.fonts
dir (if dir is not there create one)
$ cd ~/.fonts
$ mkfontscale
$ mkfontdir
$ ttmkfdir -o fonts.dir
$ fc-cache -f -v ~/.fonts
$ fc-cache -f -v
$ fc-match NonExistingFont
You can confirm that the fonts are installed with the following command:
$ fc-list | grep "Hack"
PS: The nerd-fonts submodule is really big
GPLv2+, just like Mercurial.