Report Manager extension seems to be broken on current release 6.5.16479.6613 for Linux.
Browser console shows GET https://servername//Report.json 500 (Internal Server Error)
I did find a post (http://forum.screenconnect.com/yaf_postst9106_Extension--Report-Manager--version-5-5-required.aspx) where there was similar (or same?) problem that was supposedly fixed in 6.5 but at least in my case it's not working.
Customer support service by UserEcho