i.e. React See https://s.apache.org/upmi And https://www.apache.org/legal/resolved.html
Note that even though we "use" React in plugins.cordova.io (through an npm dependency), and not include it in our repo, I suggest we remove its usage and use Preact, a drop-in replacement (untested). I filed: https://issues.apache.org/jira/browse/CB-13025
