TikTok, the hugely popular short video app owned by Chinese firm ByteDance, said it’s opening a new center that will allow outside observers to see how it moderates content. In a blog post, TikTok’s U.S. general manager Vanessa Pappas wrote that the Los Angeles-based “TikTok Transparency Center” will later also offer outside experts access to its source code, as well as its work on data privacy...