Complex sentence: Chris Vickery is a computer security researcher with UpGuard, a Mountain View, California cybersecurity startup, best known for his discovery of several very large data leaks including voter registration leaks from the United States, Mexico, and the Philippines.
Split into simpler sentences: Chris Vickery is a computer security researcher with UpGuard, a Mountain View, California cybersecurity startup. He is best known for his discovery of several very large data leaks including voter registration leaks from the United States, Mexico, and the Philippines.