Say what the emitter actually refuses, and pin the carry in the wrappers that rewrite its lines

corpus/round-trip/opaque-carry/carry-in-wrappers.json

@@ -0,0 +1,33 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "attrs": {
+            "url": "https://example.com/quoted"
+          },
+          "type": "blockCard"
+        }
+      ],
+      "type": "blockquote"
+    },
+    {
+      "content": [
+        {
+          "content": [
+            {
+              "attrs": {
+                "url": "https://example.com/listed"
+              },
+              "type": "blockCard"
+            }
+          ],
+          "type": "listItem"
+        }
+      ],
+      "type": "bulletList"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/opaque-carry/carry-in-wrappers.md

@@ -0,0 +1,17 @@
+> ```adf
+> {
+>   "attrs": {
+>     "url": "https://example.com/quoted"
+>   },
+>   "type": "blockCard"
+> }
+> ```
+
+- ```adf
+  {
+    "attrs": {
+      "url": "https://example.com/listed"
+    },
+    "type": "blockCard"
+  }
+  ```

corpus/round-trip/opaque-carry/unknown-inline.json

@@ -52,6 +52,49 @@
         }
       ],
       "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "text": ":",
+          "type": "text"
+        },
+        {
+          "type": "blockCard"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "text": "a",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "type": "placeholder"
+        },
+        {
+          "marks": [
+            {
+              "type": "strong"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
     }
   ],
   "type": "doc",

corpus/round-trip/opaque-carry/unknown-inline.md

@@ -1,3 +1,7 @@
 Draft: :adf{json="{\"attrs\":{\"text\":\"Add a summary\"},\"type\":\"placeholder\"}"} — expected Friday.
 
 **Blocked** on :adf{json="{\"attrs\":{\"extensionKey\":\"jira-issue\",\"extensionType\":\"com.atlassian.jira.macro\"},\"marks\":[{\"type\":\"strong\"}],\"type\":\"inlineExtension\"}"} until the rebuild lands.
+
+\::adf{json="{\"type\":\"blockCard\"}"}
+
+**a**:adf{json="{\"marks\":[{\"type\":\"strong\"}],\"type\":\"placeholder\"}"}**b**