> This is sad :( hetzner charges extra for ipv4 address, and this means I couldn't run `git clone` without paying extra

Well, they added the Option, so you can get your server for less then normal. The Servers are cheaper, if you Opt-Out of IPv4. I really liked that move.

with no NAT64 gateway or something similar to it?

pretty lame by hetzner if that's the case

Hetzner has an official NAT64/DNS64 gateway you can use with their v6-only offerings.

I can't seem to find any documentation on this. Details?

Think of it as providing a discount for going v6 only. Every single provider is charging you to have a v4 address. They aren't charities. Some providers just let you opt out of paying for that.

I think v6 only server but also have like NAT64/DNS64 (or just a HTTP proxy) for v4 internet access is practical for now. Even if dedicated IPv4 address isn't needed, most people may want v4 internet access.

IPv4 is only 0.64€ upsell

Unless you have a dedicated server, then it is quite a bit more expensive.

2 euro if you want one primary ip is not that bad. If you want extra, yes, they charge more for a setup (20 up front for 1, still only 2 quid per month extra).