'''FISSION:''' The links are sites explaining the Firefox's Project Fission. This is the reason for the processes you see in task manager. You can turn fission off by setting it to false on the about:config page. see screenshot Here is more info. https://www.ghacks.net/2016/02/15/change-how-many-processes-multi-process-firefox-uses/ Introducing Firefox’s new Site Isolation Security Architecture https://hacks.mozilla.org/2021/05/introducing-firefox-new-site-isolation-security-architecture/ Firefox's Project Fission: better security and more processes https://www.ghacks.net/2019/02/07/firefoxs-project-fission-better-security-and-more-processes/