And [`gpg(1)`](http://linux.die.net/man/1/gpg) says of `--export-secret-subkeys`:
- \[This\] command has the special property to render the secret
+ [This] command has the special property to render the secret
part of the primary key useless; this is a GNU extension to
OpenPGP and other implementations can not be expected to
successfully import such a key.