It’s interesting that the author and most others went with 403, when 426 seems to be the most appropriate.
Neither are perfect matches, since 403 is about authentication and 426 is for Upgrade semantics (i.e. the upgrade is over the same transport protocol, not switching from http to https). npm isn’t sending an Upgrade header, which is required, but I think if it sent Upgrade: TLS/1.0, HTTP/1.1 then that would be claiming they supported TLS on port 80 (STARTTLS style) - possible but unconventional.
It’s interesting that the author and most others went with 403, when 426 seems to be the most appropriate.
Neither are perfect matches, since 403 is about authentication and 426 is for Upgrade semantics (i.e. the upgrade is over the same transport protocol, not switching from http to https). npm isn’t sending an Upgrade header, which is required, but I think if it sent
Upgrade: TLS/1.0, HTTP/1.1then that would be claiming they supported TLS on port 80 (STARTTLS style) - possible but unconventional.