I am happy to announce that NPAPI plugin support will end in Firefox 85. At the start of the 85 cycle the Plugins Team plans to land changes that disable NPAPI plugin loading and display. We'll also schedule PI testing in both Nightly and Beta on these changes.
The initial landing is designed to accomplish the following:
1) Remove any evidence of NPAPI plugin support from the Firefox UX.
2) Support good content handling of missing Flash content.
3) Remove or disable tests that no longer work due to plugins failing to load.
4) Cleanup any critical areas of the codebase tied to NPAPI plugin support.
Please note full removal of plugin related code will not take place in this landing. We wanted to keep things as simple as possible such that if for some unforeseen reason we needed to back these changes out we could. This is not anticipated but it's better to be safe than sorry.
Plugin support touched on numerous areas of the codebase. The Plugins Team (David Parks) has been heavily invested in getting this first set of patches right, but it's possible we may have missed something critical. We would like to ask everyone who is aware of plugin code in their respective modules to take a look at the patches posted in bug 1675349. Please file bugs blocking bug 1675349 if you are aware of additional changes that might be needed in Fx85.
Once we get past the Fx85 Nightly testing round and Fx85 merges to Beta, removal of plugin code from various areas of the codebase will be greenlit. David has put effort into the removal of the old codebase and will post additional patches for landing in 86 in the coming weeks.
If you would like to help out, feel free to file bugs blocking meta bug 1677160 ('plugin-cleanup') related to future plugin code cleanup work. For feature related work dependent on plugin deprecation, please mark those bugs as dependent on meta bug 1455897 ('remove-plugin-support').
Internal questions or comments should be directed to the Mozilla Slack #flash-kill channel. For public discussion you can join the #plugins chat.mozilla.org channel.