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You appear to be replying to the co-founder of iFixit, so presumably he knows what he's talking about.

What he says matches their documentation as well:

>Blue LED: The iron is below 40° C / 100° F and is safe to touch.

>Purple LED: The iron is actively heating up or cooling down. Iron tip is not safe to touch.

>Orange LED: The iron has reached the user-set temperature and is ready for soldering. Iron tip is not safe to touch.