Playground
Every box rebuilds a real editor on this page · not a video, not a screenshot. The size is measured, and so is the time it took to build.
Everything here is a real Matra document. Select a few words and use the toolbar, or type / if you have ticked the slash menu.
Tick an extension and this editor is rebuilt around it
Untick it and the button goes with it
The array is the feature list. Press Enter twice here to leave the quote.
The numbers above are measured, not quoted.
Matra ships no features by default · an editor has exactly the extensions you hand it, and nothing else. These are all 76 of them, with what each one costs in gzipped kilobytes. Tick one and it is added to the document above; untick it and both the button and the behaviour go. Anything a ticked extension cannot work without is brought along and drawn outlined rather than filled.