Adding Parameters to a Public Key

[Melvin Carvalho]

I've noticed that some apps add some fields on the end of your public
key e.g. in Retroshare, the end of my key looks like this:


-----END PGP PUBLIC KEY BLOCK-----
--SSLID--5bcc296e6b3e40c859a031dd6c0d07b3;--LOCATION--home;


In this case:

SSLID=5bcc296e6b3e40c859a031dd6c0d07b3
LOCATION=home


Am I right to say that -- is used to represent a comment?

Is this kind of tagging extra data onto a public key allowed, or is it
possible to break things?