Electrolysis (e10s) is one of the core improvements for Firefox that Mozilla is currently working on. The feature adds so-called multi-process support to Firefox in a way similar to how Chromium-based browsers make use of it already.
A multi-process architecture that separates the browser's core from open websites and plugin contents improves not only the stability of the browser but also the security of it.
This should not be confused with sandboxing though even though Electrolysis is the gateway to make that happen later on.
Mozilla implemented Electrolysis in Nightly channel versions of the Firefox web browser back in February. The implementation was experimental back then and disabled by default.
Tests showed that work needed to be done, especially in regards to stability but also compatibility with add-ons.
Work has continued on Electrolysis and a roadmap was released recently by Mozilla developer Chris Peterson which puts Mozilla's current development and launch plans in regards to the feature on paper.
It needs to be noted that the roadmap is not set in stone and that bumps in the road may delay the project.
Firefox Multi-process architecture roadmap
- July 18, 2014 - Milestone 1: make E10s usable for average Nightly users but is not enabled by default.
- July 21, 2014 - Firefox 34 development begins. Mozilla wants to use the six weeks that follow to get Nightly users and add-on developers to test e10s and especially add-on compatibility.
- September 1, 2014 - Firefox 35 development begins. Mozilla plans to reach Milestone 2 in this development period. When Milestone 2 is reached, Electrolysis is at a point where it can be enabled for Nightly users.
- October 13, 2014 - Firefox 36 development begins. This is the version of the browser where Firefox's multi-process architecture will be moved from channel to channel (Nightly > Aurora > Beta > Stable) so that it is released to the stable channel of the browser on February 16, 2015.
A change in architecture is a major change and one of the consequences of implementing e10s is that there are add-ons that are not compatible with it.
Add-ons that are not compatible right now are among others Adblock Plus, LastPass, RequestPolicy, Greasemonkey, HTTPS Everywhere, BluHell Firewall or Video Download Helper.
Mozilla keeps track of add-on compatibility with e10s on the Are We e10s yet page. Here you find bugs listed that you can follow to find out if progress is being made to make the linked add-on compatible.
Many popular add-ons have not been tested yet, with the page only listing some of them.
Still, it is very likely that most add-ons that are still actively developed will continue to work as developers will fix them to make them compatible with e10s.
Other add-ons, those abandoned by their authors on the other hand may become defunct when e10s gets released to Firefox Stable. (via Sören)