Go to the software download page and hover over the rule package you would like more information about. There will be a link to the package details in window that appears.
Download page:
https://software.cisco.com/download/release.html?mdfid=286259687&flowid=54052&softwareid=286271056&release=Rules%20Updates&relind=AVAILABLE&rellifecycle=&reltype=latest
Typical package details page:
http://www.cisco.com/web/software/286271056/117954/sf-rules-2016-08-25-new.html