link/v8.md

@@ -1145,6 +1145,28 @@ sending `""` — a serialisation of "I have no fingerprint to assert" — had ev
 a sentence naming no catalog at all ("catalog  is now 8159778b"). Found by an offline probe that
 passed one by accident.
 
+It was **inline in three places** by the time it was found: the body catalogue (phase 3), statics
+and land (phase 5) and the tree (phase 7). All three now go through one
+`BridgeAssets.CatalogMismatch`, because three copies of a comparison are three chances for the next
+family to get it wrong in a way only a differently-written client would ever reveal. It is
+deliberately *not* the shape `BridgeLeases` uses for its own `expected`: there the value is a world
+property, where an empty string is a legitimate thing to expect and `!= null` is correct.
+
+Both defects are the same kind of thing and worth naming as one: **a value that means "I am not
+asserting anything" has two spellings on a wire, and a stock install finds whichever one you did not
+think about.** The plane is now checked against a stock ServUO install as a whole — every family,
+each asked with a real catalog, an absent one and an empty one:
+
+```
+cliloc.table walk                        67,496 rows, 12 pages
+body manifest / fetch                    1,095 rows; ok with a real, absent and empty catalog
+static + land fetch                      ok with a real, absent and empty catalog
+static/land carry their OWN catalog      art 66a112c1 vs body 323f284f — a cross-family id is refused
+tree manifest / fetch                    141 files incl. BOTH empty ones; all three ways
+empty files carry a VALID gzip member    2 rows gunzip to 0 bytes
+a STALE catalog is still refused         body, static and tree all 422
+```
+
 **`GZipStream` writes nothing for zero bytes of input.** The gzip header is emitted lazily on the
 first write, so a stream opened and closed without one yields a zero-length buffer rather than the
 20-byte empty member — which is not a valid gzip stream. **Stock ServUO 57.4 ships two empty