Metrics Export Width Measurement?

What is the unit of measurement for the .metrics export width?

all measurements in font, metrics and coordinates are in font units.

Thanks, @GeorgSeifert

Follow up question -

Is this Ems? Or is it a proprietary unit of its own? Trying to do some conversion calculations from a .metrics export.

It is just units. There is a setting in Font Info where you can define how many of those units you get per em.

Ok cool - thank you!

The range of the UPM setting is a bit limited. So you should stick to 1000 or 2000. You might get it up to 3 or 4000 but that might get you in trouble with some software.