A rough attempt to categorize these development areas can be found below. Some elements could reasonably be categorized multiply, which is why tags would be better than categories, so please bear with our taxonomy.
== Graphics and layout capabilities ==
=== SVG 1.1 ===
=== Canvas ===
=== XUL2D ===
=== "Reflow branch" ===
== JavaScript 2 ==
=== XULRunner ===
=== Embedding APIs, widgets, and frameworks ===
== Elements that resist categorization ==
=== Security model improvements ===
=== Extension manager ===