Cruise was a sponsor of ROSCon in 2014, but had no booth or presenters: http://roscon.ros.org/2014/#program

Nor do they have any presence I'm aware of on Github. This is in contrast to BMW, for example, who have made a number of contributions: https://github.com/bmwcarit

Anyway, just curious to what extent Cruise used (or still uses) ROS and open source software in their stack.