The old crank-set is labelled FC-M442/443.

Specified in marketing material as "Deore Class". Magnet says the 2 inner rings are steel and the outer ring is aluminium.

26-36-48. 175.

From what I can find, it would be quite cheap to replace, if I could find a place that actually has one. Seems like the crank-set and chain-rings are no longer available... Which is pushing me towards "upgrading" to the external-bearing crank-set.