The customer is requesting that they should be able to retrieve lists using Public PHP API without specifying any limit, which would retrieve the whole result set.

Example use case:
Call loadUserGroupsOfUser() from UserService (https://github.com/ezsystems/ezpublish-kernel/blob/b18ea5d1087bf04e71e0ce39f135d5dacbac9dbc/eZ/Publish/API/Repository/UserService.php#L291). Right now you have to specify a limit (default: 25). The customer would like to retrieve all groups of a user in one API call.
This possibly could be implemented using generators or a similar concept.