Historically STK provided implementation of pagination. Similar/same implementation was provided by other modules, such as RSS Aggregator in order to prevent circular dependencies where STK itself had dependency on those modules.
Since introduction of MTE, pagination have been moved to be a function of MTE and copies of implementation of pagination have been removed from Categorization and RSS Aggregator. The only remaining "copy" is one in STK which should be over time replaced by one from MTE as well to remove all duplicated code and keep one master copy (in MTE) only.