Say what each platform check is actually worth

README.md

@@ -31,6 +31,23 @@ This repository contains low-level bindings for [JoltPhysics](https://github.com
 - [x] iOS Simulator ARM64
 - [x] Browser WASM
 
+Ten runtime identifiers ship. Seven of them are checked against the real `.nupkg` before a
+release is published, and a failure stops the publish. What that check is worth differs, and the
+difference is worth knowing rather than glossing:
+
+| | how it is checked |
+|---|---|
+| the five desktop identifiers | the package is installed and a sphere is dropped onto a floor through the native library, which has to fall, settle, and settle *on* the floor |
+| `browser-wasm` | the same, under node, against the archive linked into the application at publish time |
+| `iossimulator-arm64` | an application is linked against the package and its executable has to **define** the entry points, not merely reference them |
+| `ios-arm64` | **not verified directly.** A device build needs a signing identity CI does not have. It links the same archive through the same targets file as the simulator, so the evidence is indirect |
+| `android-arm`, `android-arm64` | **not verified.** They are ordinary shared libraries loaded the way the desktop ones are, but nothing installs the package on Android today |
+
+iOS works differently from every other identifier and you do not have to do anything about it:
+Apple only lets an application load dynamic libraries that ship inside its own bundle, so the
+package carries a static archive and a `buildTransitive` targets file links it into your
+application at build time.
+
 ## Development
 
 ### Generate bindings locally