Where does slackware keep its updated sources?

If I go to a mirror, and dive into the directory for slackware64-15, I can find the sources (they no longer come with the install DVD). They do live on the mirror directory. However, if I pull the sources for that application, they are not the current version. They are the original release version. Where do I find the current version with the current Slackbuild script?

Thanks,
Chris