HOW do I STOP FIREFOX from giving me pop up windows ?

Hi, where do the pop-up windows appear? What I mean is:

• Separate browser windows open that have an address bar to a website - is it Mozilla's site? if not, what site is it?
• Panels drop down from the main toolbar in Firefox - do these provide information on updated Firefox features?
• Desktop notifications open, usually in the lower right corner of the screen - review and revoke permissions to sites you don't trust to generate notifications (Web Push notifications in Firefox)
• Unwanted content is added into the page - a screenshot would be useful to diagnose

No, this is FIREFOX giving me pop ups. FIREFOX has messages about the web page I am on blocking my web page. FIREFOX is sending them from FIREFOX about FIREFOX. I've had this on several web pages I was looking at. It won't let me do a screen print.

FIREFOX has messages about the web page I am on blocking my web page.

What kinds of things do these messages say?

And where are the popups positioned?

If they are on right side of Firefox window then they may be web push notifications from sites you have allowed to send you notifications. These web push notifications are not from Mozilla nor the Firefox web browser. You can block or revoke the sites from sending you notifications as shown in KB article link.

If the popups look like the screenshot example in https://support.mozilla.org/en-US/questions/1614662 then they are web push notifications.