How to examine logic used for a delivered live tile?

We are in the process of implementing PUM29 and Fluid.  (We're currently on PUM21, Classic, and PeopleTools 8.56.12.)

in Payroll for North America, we have a requirement to not show self-service checks which are from particular paygroups.  In Classic, we did this by modifying the page.activate PeopleCode on the page that lists available checks to view in self service.  I've made that same change on the Fluid version of the page.  In Fluid, this page is accessed with a delivered Tile on the Employee Self Service dashboard titled "Pay".  This is a live tile which shows the last pay date on it.  I need to examine the logic used to find that last pay date and possibly modify