Few months ago, Google changed sign-in procedure internally to support switch multiple accounts easily.
This is nice, but if you sign-in with checked "Stay signed in", Google saved your account information into cookie and it remain after sign-out.
As a result, Everybody can see your account id on google sign-in page.
This is not good in shared PC.
Therefor I created this addon to remove cookie that related to account chooser automatically.
When you try to sign-in Web site that is using the "Mozilla Persona" for user authentication ("Mozilla Developer Network"
for example) with Gmail address.
You have to sign-in to Google in the middle of authentication.
At that time, the check box that says "Stay signed in" does not appear on the Google sign-in page.
But it is treated as the check box is checked to "Stay signed in" state Internally .
As a result, Google saved your account information into cookie and it remain after sign-out.
Maybe my other addon "Uncheck Stay-signed-in for Google Login" will help to protect your privacy.https://addons.mozilla.org/firefox/addon/uncheck-stay-signed-in/