That's correct. Firefox currently uses one main browser process, one content process (for all tabs), and a plugin sandbox process. Multiple content processes (a

That's correct. Firefox currently uses one main browser process, one content process (for all tabs), and a plugin sandbox process. Multiple content processes (aka "e10s-multi") are coming soon, currently two content processes are the default in Firefox Developer Edition (53) and Nightly (54). More content processes will be added, though the Firefox team is quite aware of the concerns about memory usage. The next step will probably be four content processes plus a ServiceWorker process. https://wiki.mozilla.org/Electrolysis/Multiple_content_processes https://wiki.mozilla.org/Electrolysis/Multiple_content_proce...