diff --git a/proposals/coroutines.md b/proposals/coroutines.md
index 6e0857d99..e9506a617 100644
--- a/proposals/coroutines.md
+++ b/proposals/coroutines.md
@@ -625,6 +625,7 @@ The following style is recommended for library defined context elements.
 The example below shows a hypothetical authorization context element that stores current user name:
 
 ```kotlin
+// AuthUser here is a reference to the companion object, shorthand for AuthUser.Key
 class AuthUser(val name: String) : AbstractCoroutineContextElement(AuthUser) {
     companion object Key : CoroutineContext.Key<AuthUser>
 }