Phones of major vendors sold in EU still contain carrier info for the region even if they're sold unlocked.
Outside of US and China, Samsung for example ships so-called "Multi-CSC" variants of their devices which permanently apply the region and country of your device on first power-on with a SIM-card.
The required information for that is not pulled from the network but is already preloaded in the ROM of the device, a network connection can be used to get an updated version of these profiles though
Outside of US and China, Samsung for example ships so-called "Multi-CSC" variants of their devices which permanently apply the region and country of your device on first power-on with a SIM-card.
The required information for that is not pulled from the network but is already preloaded in the ROM of the device, a network connection can be used to get an updated version of these profiles though