$ git clone -n https://src.fedoraproject.org/rpms/gnome-extensions-app.git /var/lib/mock/f40-build-2218167-52593/root/chroot_tmpdir/scmroot/gnome-extensions-app
Cloning into '/var/lib/mock/f40-build-2218167-52593/root/chroot_tmpdir/scmroot/gnome-extensions-app'...
$ git fetch origin cddca498809f6a6128fddf6b122c1a10e17f9435:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-extensions-app
 * [new ref]         cddca498809f6a6128fddf6b122c1a10e17f9435 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cddca49 Update to 46.alpha