diff --git a/android/mutator.go b/android/mutator.go
index be74099..77d5f43 100644
--- a/android/mutator.go
+++ b/android/mutator.go
@@ -110,10 +110,17 @@
 	RegisterVisibilityRuleChecker,
 
 	// Apply properties from defaults modules to the referencing modules.
+	//
+	// Any mutators that are added before this will not see any modules created by
+	// a DefaultableHook.
 	RegisterDefaultsPreArchMutators,
 
 	// Create an association between prebuilt modules and their corresponding source
 	// modules (if any).
+	//
+	// Must be run after defaults mutators to ensure that any modules created by
+	// a DefaultableHook can be either a prebuilt or a source module with a matching
+	// prebuilt.
 	RegisterPrebuiltsPreArchMutators,
 
 	// Gather the visibility rules for all modules for us during visibility enforcement.