$ git clone -n https://src.fedoraproject.org/rpms/rust-git-absorb.git /var/lib/mock/f40-build-2150199-50894/root/chroot_tmpdir/scmroot/rust-git-absorb
Cloning into '/var/lib/mock/f40-build-2150199-50894/root/chroot_tmpdir/scmroot/rust-git-absorb'...
$ git fetch origin c42f49e15ccb54f8a8bffbec25901c672a37fe92:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-git-absorb
 * [new ref]         c42f49e15ccb54f8a8bffbec25901c672a37fe92 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c42f49e Update to version 0.6.11; Fixes RHBZ#2252020