On your link page:
 
	 5  chrome/browser/flag-metadata.json 
 
	@@ -3179,11 +3179,6 @@
 
	"owners": [ "//device/vr/OWNERS", "xr-dev@chromium.org" ],
 
	"expiry_milestone": 76
 
	},
 
	{
 
	"name": "windows10-custom-titlebar",
 
	// "owners": [ "your-team" ],
 
	"expiry_milestone": 76
 
	 
 
	As all the flags are purely experimental, they are subject to being removed at any time. They allow functionality for a time and then remove it later. Removing the /flag is easy but removing all the function code takes time.