I'm preparing a plugin which triggers a file download but it get's blocked because the widget iframe's sandbox attribute it missing "allow-downloads". Did you leave it out intentionally or is there a chance you're adding it in some of the next versions?
I'm receiving this error:
Download is disallowed. The frame initiating or instantiating the download is sandboxed, but the flag ‘allow-downloads’ is not set. See https://www.chromestatus.com/feature/5706745674465280 for more details.