I've found a hint. Apparently, both context.TODO and context.Background
share a common implementation but they need distinct addresses.
See https://golang.org/src/context/context.go#L168
So they cannot be constants because then they would not have an address.
They cannot be variables because th
x/crypto/ssh does support OpenSSH's ed25519 private key files.
However, it looks like it does not support encrypted private keys in the
OpenSSH format.
See
https://github.com/golang/crypto/blob/9f005a07e0d31d45e6656d241bb5c0f2efd4bc94/ssh/keys.go#L922
and https://github.com/openssh/openssh-po