Is there centralized control access for html5 notifications permissions?

Question

the desktop notifications permissions used by websites to control the creation of desktop notifications—for things like email and twitter—seems to have no centralized control. looking around i found the permissions manager (about:permissions) and the alert slide effect toggle in about:config but neither of these seem to have the permissions for the display of notifications.
as far as i can tell the only place i can go to control these permissions are the individual pages themselves for which the permission was granted, under the page info > permissions tab. this would be fine but if i wanted to revoke this/these permissions globally i would need to remember and revisit all websites to which i had granted the permission.
permissions manager seems like it was made for just such a purpose: to centrally locate global and individual permissions granted to websites. but the websites that i have granted this permission do not even show up in the list. i find this curious as in those pages "view page info" > permissions tab the same permissions that other sites have that are listed in permissions manager are listed directly above the notifications permission in the page info window.
is there a centralized control for the notifications permission? if yes; where is it? if no; could it please be implemented?
chrome has notification permission control in their advanced settings. easy to find. not like about:permissions.

Answer 1

i should have stated in my original question: i am using firefox 27.0.1. my addons/extensions consist almost entirely of privacy and developer themed addons ie: noscript, priv3, ghostery, firebug, jsonview, and html validator.
the exceptions button you referred to in the security tab is not for allowing collective things. that button is for listing the sites allowed/denied to install addons. i checked every page and every button in the options window before i started looking online for information about notifications. that is how i found the about:permissions page.
the functionality of notifications i refer to is built into firefox. it is not from a addon/extension as the desktop notifications work while i am running in safe mode. so no, it is not a third party addon. if it were then the management of the permissions it is granted would be done through it. there are likely addons i could get for desktop notifications but i doubt they would be using the html5 spec notifications feature and thus not useful for my purposes.
for reference the specific website that brought this feature to my attention and hence the management thereof was mail.google.com. on the general tab of the settings page for your inbox allows you to turn on or off desktop notifications of incoming mail as it is received. if you turn on the notifications the browser will ask you to grant or deny permission to the site for the display of notifications. a few days later i was thinking about these notifications and was curious how i would go about revoking the permission after it had been granted. i knew how to turn off the display of notifications by gmail, but that was not the same as revoking the permission. this search ultimately led me here.
as i stated before the permissions of a site can be viewed by looking at the page info > permissions tab, accessible from the right click menu on the page. this however, as guigs2 found, seems to be the only place where the notifications permission is found. if it were also available on the about:permissions page that would satisfy my desire for a centralized control system of the notifications permission.