Base16 for Xcode
NOTICE: I have not maintained or kept this theme up to date with whatever upstream changes may have happened to base16. You might want to check out https://github.com/kreeger/base16-xcode instead, it is now listed as the official Xcode version.
Should work with versions of Xcode 4 or newer.
cd ~/Library/Developer/Xcode/UserData/FontAndColorThemes git clone https://github.com/joedynamite/base16-xcode Base16 ln -s Base16/* ./
cd ~/Library/Developer/Xcode/UserData/FontAndColorThemes/Base16 git pull