As I was checking to see if anyone had replied, I'm hoping the lack of response is because of my incorrect wording. I didn't update 'TO' FF91, I updated 'FROM' FF91 to FF102. Hopefully that will make a differencce.

Having more content processes than in the past is because Fission is enabled in current releases. Fission is about a new site isolation architecture in Firefox and you will see more Firefox processes running than before.

• https://hacks.mozilla.org/2021/05/introducing-firefox-new-site-isolation-security-architecture/

When Fission is enabled you can no longer limit the number of content processes in "Settings -> Performance".

You can control Fission via fission.autostart on the about:config page, true to enable and false to turn it off.

• about:config => fission.autostart = false

You can open the about:config page via the location/address bar. On the warning page, you can click "Accept the Risk and Continue" to open about:config.

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

When Fission is disabled you can modify the number of content processes via Settings.

• Settings -> General -> Performance
• remove checkmark: [ ] "Use recommended performance settings"