That site is an unsupported third party site that is not part of the KODI project. It's also for IPTV, not TV listings. I don't recommend it since some of these sites cause problems with KODI.
The IPG data is not usually used by KODI itself. It's used by the TV backend. How this is supplied depends entirely on the backend software used. There are number of TV backends supported. They include MediaPortal, MythTV, NextPVR and Windows Media Center (WMC). TV support is provided by TV plugins included in KODI. Once the TV backend is chosen, then a method of obtaining TV data can be determined.