Firefox 46.0 has two "flags" called --recording and --recording-output. I've searched the net and nothing was said about them. Also I tried it myself - didn't notice a change.
1 Answer
Those flags introduce a new feature in Firefox which allows users to record web pages drawing for debugging purposes using Microsoft Azure. The drawing could include bitmaps drawn, and all font true-type data etc. These information in form of traces, could help in measuring performance and fixing bugs across Azure back-ends.
See Presenting the Azure Drawing Recorder, Add ability to record azure page drawing and Application Architecture on Microsoft Azure for more info. Note that this is currently only available in Microsoft platforms.
firefox "recording-output"was this which seems to explain it.