On the top-right there is a button labeled "Trusted". I don't know what it means. If you click it then it goes away or it doesn't, I forget.
Mousing over this button currently does not provide a description of what this means. All the other buttons do provide a description (title attribute) when you mouse over.
Please add a description to this button.

P.S. The "edit mode" button does have a description. But it is useless, I did not learn what it means or why I should click it by reading the description.
Those bits on the right are indicators, rather than buttons - they're not usually meant to be clicked.
'Trusted' means that the notebook has been created or run on your computer, and is trusted to display rich output containing Javascript. If you download a notebook and open it, it will initially be untrusted, so that it can't start doing things on your computer until you deliberately run code cells. I'm not sure how to explain that in a tooltip, though. ;-)
Ah thank you! Recommendation:
Trusted -- Javascript enabled for notebook display
Untrusted -- Javascript disabled for notebook display
Would this be sprint-friendly?
I agree it's confusing, because clicking on it makes it disappear, as if it had an action. It should be just a non-interactive label, instead of a clickable button.
A non-interactive label would definitely be clearer to me too as the Button UI right now is unintuitive.
If possible, can I work on this issue? 馃槉
I don't see why not @ashleytqy? Feel free to ask questions on our gitter
If it's an indicator, how come it goes away when clicked?
Most helpful comment
Ah thank you! Recommendation: