I finally got around to creating an icon for XRap the other day. I figured people use a box to package things, so why not use a box! Then I have been looking at that Mozilla globe, which is the default for XUL apps on Windows, and I noticed that most Mozilla apps have that globe integrated in their icon. So I pulled the globe from mozilla-central:
Default XUL Icon
I used GIMP to create the box. Which ended up just being a lot of trial and error with the shading on the sides of the box. I’m not too sure if the perspective is correct, but it turned out ok for someone that knows very little about graphic design.
Final XRap icon
To applying the icon to XRap is actually quite easy. Simply put the icon into:
(application name)/chrome/icons/default/
then for Windows, you will need an icon with the .ico extension, while on Linux you will need an icon with the .xpm extension. The name of the icon will be the id of your application, which will be located in the <window> element of your xul code. I believe there is another way to apply your icon to your application, through the branding content package, which must be defined in your manifest.
