$ git clone -n https://src.fedoraproject.org/rpms/rust-serde_with.git /var/lib/mock/f41-build-side-1-2897276-34636/root/chroot_tmpdir/scmroot/rust-serde_with
Cloning into '/var/lib/mock/f41-build-side-1-2897276-34636/root/chroot_tmpdir/scmroot/rust-serde_with'...
$ git fetch origin 64d95851dc0904130a31cd499946abbc2b88ae12:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde_with
 * [new ref]         64d95851dc0904130a31cd499946abbc2b88ae12 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 64d9585 Update to version 3.11.0; Fixes RHBZ#2315994