Firefox Add-ons Roadmap for 2017

“The year 2017 is an important one for Mozilla and Firefox. Multi-process will be enabled for all users of the web browser, sandboxing is introduced, the first bits of Project Quantum are integrated into the web browser, and the add-on system will be switched exclusively to WebExtensions. …”

Source: gHacks Tech News
Details  Firefox Add-ons Roadmap for 2017