allow extension defined member as only member in links object of relationship object (json-api#1658)

jelhan · web-flow · commit 07645e5218a0 · 2022-08-22T13:10:41.000-04:00
diff --git a/_format/1.1/index.md b/_format/1.1/index.md
@@ -495,6 +495,7 @@ A "relationship object" **MUST** contain at least one of the following:
     for the related resources as its primary data.
     (See [Fetching Relationships](#fetching-relationships).)
   * `related`: a [related resource link]
+  * a member defined by an applied [extension](#extensions).
 * `data`: [resource linkage]
 * `meta`: a [meta object][meta] that contains non-standard meta-information about the
   relationship.
