$ git clone -n https://src.fedoraproject.org/rpms/rust-xattr.git /var/lib/mock/f40-build-2260754-54419/root/chroot_tmpdir/scmroot/rust-xattr
Cloning into '/var/lib/mock/f40-build-2260754-54419/root/chroot_tmpdir/scmroot/rust-xattr'...
$ git fetch origin 281b9892b0fbce26f6328c099f620513ecf809e3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-xattr
 * [new ref]         281b9892b0fbce26f6328c099f620513ecf809e3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 281b989 Update to version 1.2.0; Fixes RHBZ#2253752