Production EXP

I normally don't focus on Production-related things, but while trying to obtain Average Firewood from Carpentry, I came across something called "Production EXP". What is that for?

Production EXP is pretty much what it sounds like. EXP you gain from production.

Ah. It also sounds like it would originate to something else.

You used to (and still do) gain EXP for gaining skill EXP, and this is why your EXP readout goes to two decimal places. If you, for example, failed to pick a Mana Herb, and got +0.10 to Herbalism for it, you would also gain 0.10 EXP. This EXP gain is not explicitly announced and because of the nature of skill training is usually not significant enough to make itself noticed.

G13 added the Production EXP you have noticed, which is a category of larger experience boosts awarded for creating certain items with life skills.