User-consented bug reports

[jyasskin]

A few Web APIs expose detailed information about the user's device because it's useful for debugging problems. E.g. https://developer.mozilla.org/en-US/docs/Web/API/WEBGL_debug_renderer_info. Other web APIs omit some details to avoid exposing private user information, but developers would benefit from those details from users who opt in. E.g. https://wicg.github.io/crash-reporting/. A few sites offer a "report a bug" flow (e.g. https://www.google.com/tools/feedback/) which could naturally incorporate a permission request, if the web platform allowed users to volunteer more system information.