If you were creating a file for a local transmitter, it might look like this:
[CHANNEL] DELIVERY_SYSTEM = DVBT FREQUENCY = 490000000 BANDWIDTH_HZ = 8000000 MODULATION = QAM/64
The LinuxTV.org project, the home of Linux DVB development, hosts the repository. This is a massive community-driven collection of initial scan files for countries and providers worldwide. You can download the entire repository or a single file for your region and provider.