They sign a CLA that explicitly says > 2. [...] You hereby grant to [...] a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright

They sign a CLA that explicitly says > 2. [...] You hereby grant to [...] a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license [...] and > Except for the license granted herein to [...], You reserve all right, title, and interest in and to Your Contributions. I am amazed that their S-1 includes language such as the one shown in the article.