Target Environments

OS-by-browser combinations are ranked by user share and summed from the top until cumulative coverage reaches 95%; the count of those combinations is this number. The "View test matrix" button opens that same ranked list with a cumulative-coverage bar and the 95% threshold line.

Imagine engineering is about to run regression tests before a major release; instead of spending time on dozens of possible OS-browser combinations, they cover only these few environments and still guarantee 95% of real users. A drop in this number means your audience got more concentrated, good news for the QA team; a rise means environments spread out more and testing resources need to grow.