- [sec] - The following is a secret key
- [ssb] - The following is a secret sub key
The meaning of # after each of these is that the key is not usable, if say, you used the export subkeys option or if the key is otherwise taken "offline".
The meaning of > is that the key is stored on something like a smart card.
You can find more info here at Ubuntu's man page for GPG and the documentation you reference has been moved to here at GnuPG.org.