Ironing symbol on skirt

[Georgyporky]

I've just bought a Chinese-made skirt from Amazon.
The fabric is very fine polyester, label says wash @ 40, don't bleach or tumble dry

But the ironing symbol is odd.
There's no number inside the symbol, nor is it crossed out, but underneath it is a wavy line.
I can't find it on Google, any idea what it means, please?

I would hazard a guess its steam. So hit enough for steam to be used but must use with steam coming out too.

hot, not hit