Hi Daniele, cool slides.
Slide 11 should probably be removed, unless you want to talk about in-progress stuff. Indeed, the "useless rules" feature has not landed yet.
Slide 43 mentions Valence which, unfortunately, we haven't had time to work on much in the past, and we don't have any automated tests for, so it's essentially unmaintained for now. So I'm not sure how valuable it is to talk about.
Other than this, great content!
Maybe you could add more console tips and tricks, lie the
copy() function which evaluates whatever is inside the parenthesis and copies the output toString value to the clipboard.
Also, right clicking on a node in the inspector provides some cool stuff: scroll into view, copy CSS path or xPath, use in console, etc.
In terms of new stuff, both the console (only in nightly for now) and debugger have brand new UIs. And the netmonitor, although it has the same UI as before, has been entirely rewritten: https://hacks.mozilla.org/2017/06/network-monitor-reloaded/
And of course, the new Layout panel (in nightly too) is a cool new addition to the inspector: https://hacks.mozilla.org/2017/06/new-css-grid-layout-panel-in-firefox-nightly/
Hope that's helpful.