Someone told me the timetable export says “unsupported file type” on their phone, and then mine did it too, which at least made it easy to chase. Turns out the plugin I use picks the file type from a big list of extensions and there is no entry for ics, so it falls through to / and Android hands that to whatever generic file previewer the manufacturer ships, which obviously cannot read a calendar. The annoying part is the phone had the right app the whole time, because Honor’s calendar registers itself for text/calendar and I just never asked for it. One extra argument and the export now offers the calendar first, which ships in the next update.