To encourage people to (a) make the switch, (b) or at least try Treeherder so they file bugs for any remaining blockers etc.

I've used the existing showMessage() function for simplicity. To get the EOL message to (a) stand out and (b) persist until closed, I've set the message type to "error". I've added as two separate messages, since it's not possible to insert newlines, and again I'd like it to stand out. (It's probably not a bad thing that this also means it requires two clicks to close, might give more of a nudge). I've adjusted the opacity of the message banner, since previously you could see too much of the page behind, making the fairly long message (compared to what is normally displayed there) hard to read.

Meant to say - since TBPL isn't tier 1 as it were any more, I think we can be a bit more relaxed about changes/review from a correctness point of view. I've tested this locally, so this review is more of a feedback request on the choice of wording, so don't worry if you don't have much time to take a proper look :-)

Comment on attachment 8547189 [details] [diff] [review] Add EOL notice/banner on initial pageload (Have a slightly tweaked version of this patch, but mainly testing a bugzilla-todos bug)

remote: https://hg.mozilla.org/webtools/tbpl/rev/928dc210f588 +deployed