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/

The change didn't worked and even after changing the config value to a smaller number, firefox was independantly spawning a loot of child processess (minimum 30), even if there was opened only the dashboard or a about:blank page.

Any attempt's of clossing them thru a process manager were failing because them were restarted (restored) short after killing.

Prefered solution:

When starting Firefox, there should be created few "container" child-processess (one for each kind) in with remaining child processes would be spawned. The example main "containers":

• for extensions
• for browser utilities
• for content

In the content container, each page should have own sub-container. This way, It would be able to close it separatelly (for example if it stop ro response), without need to close firefox or kill it's process.

Additionally:

• there should exist in "about:config" options to precise control the processess

• garbage collectors, etc. should do anything instead of pretending doing it

What do you have set here. https://support.mozilla.org/en-US/kb/performance-settings The answer here may also help. https://support.mozilla.org/mk/questions/1412530

After unchecking the "performance" option, the next options to control the efficiency not always appear.

Additionally, changing of some performance settings in the "about:config" seem to have no effect