[internetionals]

A Large part of the reason they couldn't easily address the UI performance was because of the old extensions.

The reason that Firefox switched to webextensions was in order to switch to a formal extension API that could be supported long term, instead of the old open integration API which made it difficult to readable without breaking all sorts of extensions.

There reason they adapted the web extension API that chrome uses, was because it largely made sense, was already pretty fleshed out and would allow extension writers that were already familiar with that to also target Firefox.

[bigbugbag]

Also the fastest way to accelerate the bleeding of long time supporters and power users who would not be using firefox if not for extensions.