+/* If payload is a cryptographic payload within an encrypted message, and
+ * it has a "legacy display" part, then we can skip over it and jump
+ * to the actual content, because notmuch already handles protected
+ * headers appropriately.
+ *
+ * This function either returns payload directly (if it does not have
+ * a "legacy display" part), or it returns a pointer to its
+ * content-bearing subpart, with the "legacy display" part and the
+ * surrounding multipart/mixed object bypassed.
+ *
+ * No new objects are created by calling this function, and the
+ * returned object will only be released when the original part is
+ * disposed of.
+ */
+GMimeObject *
+_notmuch_repair_crypto_payload_skip_legacy_display (GMimeObject *payload);
+