diff --git a/blink/public/devtools_protocol/browser_protocol.pdl b/blink/public/devtools_protocol/browser_protocol.pdl
index ec01d88f7dc..b5b9d191e8b 100644
--- a/blink/public/devtools_protocol/browser_protocol.pdl
+++ b/blink/public/devtools_protocol/browser_protocol.pdl
@@ -7849,6 +7849,7 @@ domain Page
       BrowsingInstanceNotSwapped
       BackForwardCacheDisabledForDelegate
       OptInUnloadHeaderNotPresent
+      UnloadHandlerExistsInMainFrame
       UnloadHandlerExistsInSubFrame
       ServiceWorkerUnregistration
       CacheControlNoStore