That’s DNS64, which is pretty annoying in practice. (For one thing, you can’t use your own DNS server anymore, but more importantly, anything using v4 literals will 100% break.)

What’s nicer is 464XLAT, or more generally NAT64 prefix announcements. Then your local OS can just synthesize NAT64 addresses from v4 literals, either at the socket library or kernel networking (via “bump in the stack” translation) layer.