This feature has already ridden the release train (currently in 57 beta) [1] and should be released with Firefox 57 next month. [1] https://www.mozilla.org/en-

This feature has already ridden the release train (currently in 57 beta) [1] and should be released with Firefox 57 next month. [1] https://www.mozilla.org/en-US/firefox/57.0beta/releasenotes/ https://www.mozilla.org/en-US/firefox/57.0beta/releasenotes/