The ECHO object each pair of a pathname names, in order, without a key table. Keys can never be
EntityId-shaped (the graph builder drops them at registration, mirroring isReservedKey), so
a segment holding an EntityId is an id and the segment before it is its key. A tail joins the node's
ancestors before it (<mailboxId>+<messageId>, <schemaId>+<objectId>), so the last EntityId is the
object. Empty for a pathname that does not open with /<anchor>/<workspace>.
The ECHO object each pair of a pathname names, in order, without a key table. Keys can never be EntityId-shaped (the graph builder drops them at registration, mirroring isReservedKey), so a segment holding an EntityId is an id and the segment before it is its key. A tail joins the node's ancestors before it (
<mailboxId>+<messageId>,<schemaId>+<objectId>), so the last EntityId is the object. Empty for a pathname that does not open with/<anchor>/<workspace>.