$ git clone -n https://src.fedoraproject.org/rpms/rust-gtk3-macros0.15.git /var/lib/mock/f38-build-side-43-rust-devel-1411258-31430/root/chroot_tmpdir/scmroot/rust-gtk3-macros0.15
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1411258-31430/root/chroot_tmpdir/scmroot/rust-gtk3-macros0.15'...
$ git fetch origin 213a098e3f663de27e352f1514bf5d2797f690b5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gtk3-macros0.15
 * [new ref]         213a098e3f663de27e352f1514bf5d2797f690b5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 213a098 Update to version 0.15.6