About:support or troubleshooting information page in Firefox is one stop place where you can check system add-ons installed in the browser, Reset if you’ve any issues with it, check Firefox version, open Profile folder and see the Profile path.
By visiting about:support page, you can know whether Firefox has Multi-process or e10s support and accessibility enabled or not and other information.
All the information on this page is divided into sections. In the Firefox 59, Mozilla has added Security Software section, that fetches information from Windows Security Center on Windows 8/8.1 and Windows 10 and displays the data about Antivirus, Antispyware and Firewall installed on your computer.
In version 59, Firefox displays search suggestions first, followed by suggestions from history and open tabs, which you can change by unchecking a checkbox in Search preferences.
For more details, read: Firefox 59 : Show History Suggestions first in address bar results
If you want to know more about changes coming in Firefox 59, check out the below links