$ git clone -n https://src.fedoraproject.org/rpms/rust-either.git /var/lib/mock/f40-build-2655431-66911/root/chroot_tmpdir/scmroot/rust-either
Cloning into '/var/lib/mock/f40-build-2655431-66911/root/chroot_tmpdir/scmroot/rust-either'...
$ git fetch origin 86754b31bf14e6693179adb7ca5a0043961ba7c9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-either
 * [new ref]         86754b31bf14e6693179adb7ca5a0043961ba7c9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86754b3 Update to version 1.10.0; Fixes RHBZ#2263610