src/tools/xcode/ibtoolwrapper/README - bazel - Git at Google

 ibtoolwrapper runs ibtool, which compiles storyboards and xibs etc.
 ibtoolwrapper then zips up the output,
 because ibtool returns an unpredictable number of output files.

 ibtool only runs on Darwin, so ibtoolwrapper only runs on Darwin.
	ibtoolwrapper runs ibtool, which compiles storyboards and xibs etc.
	ibtoolwrapper then zips up the output,
	because ibtool returns an unpredictable number of output files.

	ibtool only runs on Darwin, so ibtoolwrapper only runs on Darwin.