$ git clone -n https://src.fedoraproject.org/rpms/fedora-distro-aliases.git /var/lib/mock/f42-build-side-1-3497656-45961/root/chroot_tmpdir/scmroot/fedora-distro-aliases
Cloning into '/var/lib/mock/f42-build-side-1-3497656-45961/root/chroot_tmpdir/scmroot/fedora-distro-aliases'...
$ git fetch origin e2ff73a541784f9034abc0b74a87d6e4dca2387b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-distro-aliases
 * [new ref]         e2ff73a541784f9034abc0b74a87d6e4dca2387b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e2ff73a Update fedora-distro-aliases to 1.7-1