Time zone names

Espruino does not have a time zone subsystem of its own to store the rules

As above, Espruino does, but it's not used apart from via widdst - as you noted, Gadgetbridge just sets the timezone offset right now, so I don't think getIsDST will work by default.

But yes, if someone wanted to make Gadgetbridge send that extra data, that'd be really handy - as long as it didn't end up breaking things for users.

However, if you wanted something right now without having to mess with Gadgetbridge and potentially Bangle.js internals then could you not look at (new Date()).getTimezoneOffset() in your clock face and then just look the abbreviation up in an array on the watch?

I know there are different abbreviations but it seems like realistically most people would agree on the main ones like CET