$ git clone -n https://src.fedoraproject.org/rpms/libucontext.git /var/lib/mock/f45-build-17133-496/root/chroot_tmpdir/scmroot/libucontext
Cloning into '/var/lib/mock/f45-build-17133-496/root/chroot_tmpdir/scmroot/libucontext'...
$ git fetch origin 2cb9cdb42801f6487bf0fe8fb7b9e6fea0e6ad97:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libucontext
 * [new ref]         2cb9cdb42801f6487bf0fe8fb7b9e6fea0e6ad97 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2cb9cdb Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild