https://www.bleepingcomputer.com/news/software/mozilla-to-disable-flash-plugin-by-default-in-firefox-69/

Starting in Firefox 69, Mozilla will be disabling support for the Adobe Flash plugin by default. This is being done as part of the roadmap set forth by Mozilla on how they will be ultimately disable all support for Flash in Firefox.

In July 2017, Adobe announced that Adobe Flash would have an end-of-life in 2020 and that other technologies such as HTML5, WebAssembly, and WebGL have matured enough to fill the gap. In a coordinated announcement, major operating system and browser companies such as Microsoft, Google, Apple, and Mozilla announced a similar plan to block Adobe Flash from running within their software in 2020 as well.