What's mysterious about it?

How did they do it without EUV?

It's perfectly possible without EUV, if you're willing to accept high defect rates. That's one reason why the chip bans can never have military effects (the other is that current military hardware doesn't need the smaller nodes) - only commercial effects.

But the Huawei phone. I suspect the government is subsidizing that chip.

7nm is just a word.

Maybe its right at the edge of what the old UV machines can do with double patterning and such.

That’s my thinking — a low yield version of TSM N7+, maybe?

TSMC N7 doesn't use EUV and SMIC 7 nm is a copy of N7.

My understanding is that this is closer to N7+, which does.