It went through various iterations and is now at version 3 (dating from 1995) and used in a variety of clientserver applications.
Since the demise of Netscape the SSL specifications will not be updated further.
Note: SSLv2 was banned by RFC 6176 which contains a dire list of its shortcomings.
SSLv3 has now joined its older brother in being banished by RFC 7568.
We've also added some info on the contents of various file types (.pem, .p12, .pfx, .der, .cer), PEM keywords and a PKCS to RFC mapping list.
You can either buy an SSL (X.509) certificate or generate your own (a self-signed certificate) for testing or, depending on the application, even in a production environment.
We started doing this a long, long time ago when RFCs were maintained in some strange places, occasionally moved location, and performance and reliability of the repositories was very variable (being generous). The IETF, like IANA, have solid web sites with excellent performance and continually improving features.