about:permissions page aka the built-in permissions manager in Firefox, which was introduced with Firefox 6, has been removed in Firefox 45 (which is currently in Nightly). Till now this page has allowed to configure permissions given to websites for storing passwords, geolocation, cookies, Camera, Microphone, pop-up windows, offline storage and other things from one place in Firefox browser.

How to access and manage site-specific permissions in Firefox 45 then?
You can still able to access permissions UI in Firefox 45 without need to visit about:permissions, here is how: Right click on page, select ‘View Page Info’ and select ‘Permissions’ .

If you don’t know Firefox 45 also sees the removal of tab groups and Mozilla has announced it will stop support for complete themes (heavyweight themes) soon in their browser also.
What do you say on this change? Will you miss about:permissions page?