poky/meta/classes/metadata_scm.bbclass

METADATA_BRANCH := "${@oe.buildcfg.detect_branch(d)}"
METADATA_BRANCH[vardepvalue] = "${METADATA_BRANCH}"
METADATA_REVISION := "${@oe.buildcfg.detect_revision(d)}"
METADATA_REVISION[vardepvalue] = "${METADATA_REVISION}"