Feature parity is impossible. Webextensions are intended to take away possibilities like altering the UI or calling out to external programs. So webextensions w

Feature parity is impossible. Webextensions are intended to take away possibilities like altering the UI or calling out to external programs. So webextensions will never ever be on feature parity with XUL addons. Also, changes to webextensions are proceeding at a snails pace, suggesting that Mozilla doesn't really intend to get anywhere close to working support for e.g. keybinding remapping or anything like that. If you are waiting for more powerful webextensions, abandon all hope. Change is not coming.