On page https://e621.net/post_sets/new
There's link set:example which redirects to https://e621.net/post?tags=set%3Aexample
On that page I get message
Access Denied
You do not have permission to visit this page.
This happens on both chromium and firefox, on linux
I assume set:example is same as https://e621.net/help/sets
Edit: Link works now, Cinder was quick to fix it
Updated