It looks like AppCache has been deprecated since Firefox 44 (https://www.fxsitecompat.com/en-CA/docs/2016/application-cache-support-will-be-removed/ ) and that it has now been completely removed from FireFox.
It looks like AppCache has been deprecated since Firefox 44 (https:/ /www.fxsitecomp at.com/ en-CA/docs/ 2016/applicatio n-cache- support- will-be- removed/ ) and that it has now been completely removed from FireFox.