One of the teacher notes links is dead
The "Safari 9 will support unprefixed transform properties" link under "Browser Support" in the Teacher's Notes of this video is dead.
Simon Coates4,069 Points
Actual verifiable mistakes should likely be reported directly to email@example.com . Unless the broken link is temporary, it definitely seems like something for them to update. (In the past, I have had difficulties convincing support people of issues. They do occasionally try to offload you into the public forum, but a dead link seems unambiguous and like something that should be fixed on a currently active course)