diff --git a/docs/design.md b/docs/design.md
index 9c27c9f..7f7426e 100644
--- a/docs/design.md
+++ b/docs/design.md
@@ -243,6 +243,18 @@ number, `productdata/<id>/<revision>/`) but hardly shows them; T5DE shows them o
   Pictures\T5DE badges, made by its `draw.py`): badges 18x14, 25x21 and 23x19; filter strips for IMVU's two
   layouts with T5 added last (`GA|all|AP|T5`, `GA|AP|AP+|all|T5`) and `all|T5` for people without Access Pass,
   who get no rating filter today (T5 products aren't only adult ones).
+- **Where the T5 badge goes** (every place the client shows AP/AP+/VIP badges, checked in the client's UI files):
+  - *Products and outfits* (always, a property of the product): shop results and product pages, inventory,
+    the outfits viewer and outfit cards (an outfit with any T5 product gets it, as AP outfits do), product
+    recommendation widgets, checkout ("getting" a T5 product).
+  - *People* (only if they turned on "Show T5DE badge" for that IMVU account, the same choice everywhere): avatar
+    cards, the friends list (page and sidebar), the right-click menu on an avatar, chat names, the inbox, the
+    "invited to chat" and Shop Together invite dialogs, the gifting friend picker, home, and Find People and Get
+    Matched (with a "T5DE users" filter there).
+  - *Rooms* (always, not optional: visitors need to know a room needs T5DE to be seen as meant; hosted rooms, and
+    IMVU rooms decorated with T5 products): the chat rooms browser, room cards, the owner's room manager, and the
+    room's tab.
+  The client learns who and what is T5 from the proxy, which asks the hub (badge choices, products, rooms).
 - Needs: the hub's product registry and catalogs serving files (so products don't have to be local packs), the
   library on the hub, the proxy answering the inventory's and shop's calls for T5 products, and a patch to the
   shop page for the filter and badges.