Apple has been working on CUPS 1.6 for some time and unlike previous releases, this time, besides bug fixing and adding new features, they are trying to remove some items which are no longer needed in Apple Mac OS, such as CUPS filters and backend. They also did not accept the new filters for the PDF-based printing workflow as they are also not used by Mac OS X. This filters and backend has been moved to OpenPrinting and as a results, a new package has been released: cups-filters. This package will be a complementary package for the base CUPS package maintained by Apple just in case you need those filters and backends.
I have prepared a special branch on my SlackHacks called cups1.6 which i will use as a testing ground for the upcoming CUPS 1.6. I have updated the SlackBuild script to compile cups 1.6rc1 and also added a SlackBuild for cups-filter package.
Please note that cups 1.6 is still in RC, so it's not suitable for daily usage on production machines. Also, don't use cups-filters along with cups 1.5.x. It's designed to work with cups 1.6.x branch.
Should you decide to test, let me know if there's something wrong with my SlackBuild. I will happily update it for you.
I don't think Slackware 14.0 will include cups 1.6 as their default package, so this is just really an early preparation for the upcoming cups 1.6. Don't bother mailing Patrick Volkerding to include this into Slackware 14. We don't need new major changes for now and let him and other Slackware team work on stabilizing Slackware-Current which soon to be released as Slackware 14.0.This package can wait until the next next Slackware release :)