org.danielnixon.saferdom.impl.lib
https://html.spec.whatwg.org/multipage/interaction.html#the-dragevent-interface
https://w3c.github.io/html/editing.html#the-dragevent-interface
https://html.spec.whatwg.org/multipage/interaction.html#the-dragevent-interface
https://w3c.github.io/html/editing.html#the-dragevent-interface