You can now use data-uri as background image in styled messages — Bug 1579663
Logged functions now indicates if they’re async/generator — Bug 1316265
Brian Hackett started to work on Eager Evaluation — Bug 1602489
The Changes and Fonts sidebar panels should be a lot easier to use when the sidebar is narrow. More work coming in the other panels soon! (1599408, 1599409)
The Shape Path editor now makes it possible to edit default ellipse shapes too (1598109).
RDM now shows browser and OS information of simulated devices (1306198)!
VariableViewController was removed — Bug 1529917
VariableView was moved to storage folder, its last consumer — Bug 1591874