Firefox and WebExtensions
Do you know that Firefox now have a new technology that simplify the development of an extension? And also use and extend the API of Chrome? Yea, I am serious you can do an extension for both the browsers!
WebExtension are the future for addons in Firefox but this is not enough because they works also on Chrome, Opera and soon Edge without any changes!
Think about it, the cross browser addon issues are only an old nightmare! In conclusion because all this amazing news and how it is easy to extend Firefox will be available new APIs to customize the the Firefox experience in this year.