Nikon SnapBridge and Photos

I've been looking at SnapBridge as a way to geotag photos taken with my Nikon Z5 before transferring the images to Photos. I think I got SnapBridge working fine. When I tell SnapBridge to automatically upload pictures as they are taken, they are loaded into Photos, and synced to my devices fine. On my iPhone or iPad, when I check the Info for a photo uploaded this way, I see the notice "Saved from SnapBridge" at the bottom of the info window. I don't see this if I view the info for these pictures on my Mac. I can enter "SnapBridge" in the search window and Photos does find these SnapBridge photos. Does anyone know where or how Photo tags these photos as coming from SnapBridge? I can't find it any of the EXIF data. I'm just curious. I probably wouldn't transfer my photos this way from my camera and would only transfer directly from the SD Card. I'm just trying to really understand SnapBridge. Thanks in advance.

Ed