Filesystem:/System/Library/Carrier Bundles

Every carrier settings is in this folder. Visual Voicemail, carrier logo, MMS settings, Facetime settings and provider bookmarks in safari. Every folder has a shortcut with a number (from 00101 to 74810). If you for emaple using a AT&T SIM card the bundle "ATT_US.bundle" will be copied to var/mobile/Library/Carrier Bundles. There is also the shortcut with the number of this carrier bundle. The number is the prefix of the IMSI of supported sim cards. For example "310180" (AT&T uses more than 1 bundle). There is also a shortcut of the folder in var/mobile/Library/Carrier Bundle.bundle.