These are probably just implementation bugs, but it's somewhat curious that no browser handles
WWW-Authenticate: Newauth realm="apps", type=1, title="Login to \"apps\"", Basic realm="simple" from the standard correctly. They all do handle

WWW-Authenticate: Newauth realm="apps", type=1, title="Login to \"apps\""
WWW-Authenticate: Basic realm="simple"

correctly on the other hand.

I'll create some manual tests for web-platform-tests, unless someone has a good idea on how to automate this...