Why is the use of chrome/firefox extension mandatory?

In a scenario for using passbolt as an internal application to save passwords for all kinds of applications (on only web apps), the mandatory use of chrome/firefox extension is not appropriate from my perspective.

I can see you’ve open sourced the development of these (GitHub - passbolt/passbolt_browser_extension: Passbolt browser extensions (Firefox & Chrome)), but for trusting purposes I’d like to understand why they’re required specifically.

Would you be able to provide a documention/blog article for non/semi-technical people?

See. Why does passbolt require an extension? | by passbolt | passbolt | Medium