Starting from Firefox 69, Mozilla will disable Adobe Flash by default, a process that aims to completely remove the support for the plugin. In July 2017, Adobe announced plans to completely kill Flash and stop providing security updates for it by the end of 2020. Many vulnerabilities in the popular plugin were being actively exploited in cyber attacks in the wild. From 2020 Mozilla will no more support Flash in the consumer versions of Firefox, only the Firefox Extended Support Release (ESR) will continue to continue to support it until 2020. The change will land in the 69 Nightly cycle and ride the trains.”]
Source: https://securityaffairs.co/wordpress/79885/hacking/firefox-69-disable-flash.html