The about menu item from the Add-on Manager should open about:scriptish
Reported by Scriptish | September 18th, 2011 @ 09:53 PM
Possible other consumers of em:aboutURL, too.
Implement this by using a stub XUL "window" that in turn opens a
new about:Scriptish tab within the most recent browser.
Do not use window.opener tricks or such, as there is no guarantee the opener will be a browser.
While there might be minor flickering (depending on platform) when the "window" opens, this is still the least intrusive and probably most compatible way to do this.