To speculate: the AGPL is the most common license that keeps to the spirit of free software when it comes to licensing for anything that could possibly be used

To speculate: the AGPL is the most common license that keeps to the spirit of free software when it comes to licensing for anything that could possibly be used in a web-facing product. If they didn't use it, it's likely that someone would have made a company profiting off of their work by now.