.XCCOLORTHEME File Extension
What is an XCCOLORTHEME file?
File used by Apple Xcode, a program used to develop iOS and Mac OS X applications; contains data that describes the color theme of the code editor; includes the text color, text font, and text background color of different elements of source code editing, such as Plain Text, Strings, URLs, Attributes, and Comments.
In order to select your theme, you must place your XCCOLORTHEME file in the ~/Library/Application Support/Xcode/Color Themes directory. If the "Color Themes" folder doesn't exist yet, simply create that folder and restart Xcode. Then, you can select your color theme in the application. Select Xcode → Preferences..., choose "Fonts & Colors, select your theme, and click Apply.
NOTE: .DVTCOLORTHEME files replaced XCCOLORTHEME files in Xcode 4.