That is the way sync is set up. Bookmarks, history, password/logins . . . .

What if I don't want to sync passwords, or apps, as an example.

I have several profiles. Currently, If I enable sync, it immediately goes to work, not giving the opportunity to pick and choose what I want. I end up swamped with a bunch of junk from the past, and things that don't apply to the profiles unique task application.

And I don't know where the sync is coming from. None of my current desktop profiles are set up to sync, only my mobile.

Type about:preferences#sync<enter> in the address bar. Select what you want to sync. Turn off what you don't.

See:

• https://support.mozilla.org/en-US/kb/how-do-i-choose-what-types-information-sync-firefox

I don't know what I was doing different before, but I enabled Sync in my main profile, and the categories were set up the way I needed them to be, I guess from the last time I edited them, even tho I disconnected sync.

I opened up a secondary profile, enabled Sync, and that one was set up categorically the way the first one was.

I have some another questions. Which direction does the Sync go in? For instance, Is it all about the latest session overwriting an earlier one? Does that also count for everything else, including the categories chosen to sink?

There is no direction for Sync, data from all connected devices is uploaded to the Sync server and merged to all connected devices, so all devices end up with the same content.

So, If I delete a tab in one profile, it is simultaneously removed in another profile?

What happens if I have 2 identical profiles, but I only work with one for several weeks, during which time I add numerous tabs, and discard others, after which I launch the dormant profile?

Does that apply to settings? Logins and Passwords?