On a freshly installed Firefox there is a plugin named:
Default Browser Helper 537
It seems to be something from Apple but i couldn't find more information about it.
What is it and why it there?
Do we need it?
OS X 10.9 (and 10.9.1)
Firefox 25.0.1 (and 26)
Best Answer
I did some digging and documented my findings.
The plug-in is used to produce the below dialog. It can be triggered by Apple from inside any other web browser. It is unclear when and where this is used.