Thanks for reaching out Te123; I'm one of the developers working on Firefox Accounts.

> I thought I can view all devices logined to my account, but Firefox hasn't this capability.

We are working on exactly this feature, although it's not yet ready for general consumption. I hope we will be able to release it soon!

> When did you start to send notifications about new devices connected to my account?

This is a new security feature released a few weeks ago (around April 7th if I remember correctly). We're still fine-tuning the details, for example you can sometimes receive a "new login" email even if you're just changing your password on an existing device. If you have any feedback about the emails and whether they're useful to you, please let us know.

If tabs are synced then you should see a tabs from other devices item in the history.

cor-el said

If tabs are synced then you should see a tabs from other devices item in the history.

No, I only sync passwords and bookmarks.