Does Firefox share my Gmail details with web sites
I use Firefox 60.4.0ESR. I recently noticed that if I have logged into Gmail in one tab and access the site economictimes.indiatimes.com in another tab, the latter pops up a window encouraging me to sign in with my Gmail ID. In that window, this site shows my Gmail ID and my name as it is in Gmail records. The window also provides a button with the label "Log in as <MyName>".
How does that web site, where I do not have an account and visit rarely, have my Gmail credentials? Is Firefox sharing these details with the web site?