A number of users prefer dark themes, like Heiko and Joel, so providing them
with a light version of sifr and breeze that will be easily visible on their
dark theme is a good feature.
There are two means of achieving this:
1) bundling a light version of the icon theme
2) invert the colors within the software
Andreas has a script to automate the creating of a light version for breeze and
likely this same script would work with sifr with a little tweaking. Kendy
prefers that this be done within the software and will be providing code
pointers so a dev can look into that.