diff --git a/IMPLEMENTATION.md b/IMPLEMENTATION.md
index 3c82ebc..f487395 100644
--- a/IMPLEMENTATION.md
+++ b/IMPLEMENTATION.md
@@ -75,6 +75,12 @@ If in background context, the `ShimManager` is imported, initialized and the `po
If instead in a content script context, `shim/contentBridge.ts` is imported and with side-effects (background script still calls into ShimManager), it creates and exports a `backgroundPort`. The incoming messages on that port are posted to `port2` and the incoming messages on `port2` are posted to `backgroundPort`.
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In either case, `port1` as part of a message channel to the background script is resolved as the result of the `ensureInit` promise as soon as the `shim:/initialized` message is passed to the shim.
diff --git a/diagram_module.svg b/diagram_module.svg
new file mode 100644
index 0000000..b736fd7
--- /dev/null
+++ b/diagram_module.svg
@@ -0,0 +1 @@
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