[_frog]

When your target audience is 'Firefox users', doesn't it make sense to more freely use features that are supported by Firefox?

[superkuh]

Firefox is open source. There are lots of Firefox forks. Right now there are more add-ons that work in the Firefox forks then there are add-ons that work in modern Firefox.

[majewsky]

I'm going to make a guess that the same goes for exploits.