Mendix could probably give a much better answer but I do know a little more about the proces. Mendix does have a automated test street for certain widgets. As far as I know the apps developed by Mendix itself are part of this automated test street. The idear was that all the apps produced by Mendix would be checked by this teststreet. I have no information on how far this is realized. There has been some idears that other developers could also take advantage of this test street if they supplied Mendix with the testscripts. As far as I know this has never been realized.
So that is where croud sourcing comes in. And since this page is uniform it will show on all the widget pages either from Mendix or another third party. When you use a widget in a project and the widget works as expected fill in the form for which version this works and you help other developers this way. Because yes maintaining widget is hard work that most of the time is done by developers in their spare time. So yes putting a widget in your model can be a risk. You allways have to weigh that risk with the advantage of the widget.
I hope that somebody from Mendix can chime in here for a more recent status update.