Pack docs: what the client was seen to do

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/pack.md

@@ -75,12 +75,15 @@ rest:
 | `BodyPatternProductId` | optional integer |
 | `__DATAIMPORT` | optional: `product://<id>/index.xml`, the IMVU product it derives from |
 
-A product derives from an IMVU parent product, as every IMVU product does: the client loads the parent's files
-first (from IMVU, as usual) and the pack's files on top. So a pack holds only what it changes, and the parent's
-files never pass through T5DE.
+A product usually derives from an IMVU parent product (a derivable mesh), as products made in Create Mode do. The
+client asks IMVU for the parent's whole derivation chain and loads the parents' files from IMVU, and the pack's
+files on top of them: a pack file with the same name as a parent's replaces it (checked with a texture in client
+554.8). So a pack holds only what it changes, and the parents' files never pass through T5DE.
 
 ## How the proxy serves a pack
 
 The proxy builds the files into a CFL, IMVU's product container (package `cfl`), uncompressed, files in name
-order, and serves it where the client asks for the product's files. The revision is part of the address the
-client caches the product under, so a new revision makes clients load the new files.
+order, and serves it at `productdata/<local ID>/<revision>`, the address the client asks for. The client caches a
+product's files by that address and file name, so a new revision makes clients load the new files. The proxy
+picks up changed files within a revision too, but a running client may keep the files it already loaded: raise
+the revision to be sure.