I thought we had written this down somewhere but I don't see it. This came out of a discussion with @Hixie and is a nice-to-have feature, but not anywhere on our near-term roadmap. Filing as this came up in discussion with a customer the other day. The goal is to answer the question of "what devices/screensizes does my app look bad on".

Should be straightforward with flutter to attempt laying out an app/route/widget at lots of different sizes and validate that no layout exceptions (red areas) are thrown. In the headless desktop sky_shell this would be very quick. Presumably there exists a list of known Android device screen sizes/densities somewhere on the web which should be straightforward to compile.