Welcome to the forum Roger,
There are two "themed content" downloads, but the second depends on what level of membership one has at Photoshop.com.
First, there is the Addtional Functional Content, that comes with PrE. It contains a lot of Title Templates, Menu Sets, Instant Movies/Themes, and is a separate install from the program. For that material, in a download, Neale has provided a link to that material, and I think that is what you are talking about. For installation from physical media, there is another, separate disc, with that material.
Also, if one has a Plus membership to Photoshop.com, they get more on-line storage space, plus access to download some additional content. That seems to be released in small quantities, and appears to be somewhat "seasonal." It also seems that older content is removed, so that one only has a limited amout of additional content, at any one time. Some Plus members have complained that there is not much material in this area, but I cannot comment. I do not believe that this is what you are talking about, but could be wrong.
Also, there is some additional content available for free to subscribers to Muvipix.com, a PrE "companion site." There is a bunch of stock video footage, quite a few new Menu Sets, but do not think there are any Instant Movie/Themes.
Good luck, and please let us know if Neale's link is what you are referring to.