Informant shares the data for your contacts with what is in the native contacts app that came with your device.
If you have multiple sources syncing your contacts to your device (like Google, Samsung, Only on your phone, etc) then in Informant you can choose which of those sources to use.
Tap the contacts icon. Then tap the menu bars at the bottom right and choose visible accounts. From this list, choose the source(s) you want to make available to Informant to show your contacts.