Whether a folder segment is the relationships folder: its OPC-canonical
name (canonicalPartName: ASCII case folded, escapes of unreserved
characters decoded) is _rels, so _RELS, _%72els, %5Frels and
_r%65ls name it too — the same equivalence the sidecar lookup
(equivalentPartLookup) finds a stored spelling by, so the folder
a sidecar's targets resolve against is picked by it as well (#758, #772).
Whether a folder segment is the relationships folder: its OPC-canonical name (canonicalPartName: ASCII case folded, escapes of unreserved characters decoded) is
_rels, so_RELS,_%72els,%5Frelsand_r%65lsname it too — the same equivalence the sidecar lookup (equivalentPartLookup) finds a stored spelling by, so the folder a sidecar's targets resolve against is picked by it as well (#758, #772).