I think what the OP is talking about is the Apis posted and othesr like them are being blocked all over the place.

Like when i visit Kickstarter.com i get a notification for a file http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js being blocked as a URL:Mal

when i click on More details in the popup, the Avat site has a notification popup for the file http://fonts.googleapis.com/css?family=Open+Sans:400italic,700,400|Open+Sans+Condensed:700&subset=latin-ext being blocked as URL:Mal

Point being is, it is making some sites almost unusable as it blocks functionality.

As a side note going to http://sitecheck.sucuri.net/results/www.avast.com i get two URL:Mal notifications one for http://ajax.googleapis.com/ajax/libs/webfont/1/webfont.js and one for http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.1/jquery-ui.min.js

so yeah, very frustrating.

EDIT: it appears after restarting Firefox for the 5th time it has fixed itself.