I've asked @zware and @serhiy-storchaka whether this tool works.

They reported that there are problems with it.

So, there are several options at the moment:

1. @zware proposed to move it to unittest.gui, if so we need to: start a proper discussion on discourse, fix all bugs, implement this feature / add tests / docs
2. We can just fix bugs and keep it as is, maybe mention in devguide
3. We can remove it, if other people don't find it useful anymore
4. We can just keep it as-is for history
5. Anything else? :)