You found the website.... so maybe try reading through some of the FAQs in the support section: https://ledger.zendesk.com/hc/en-us/articles/115005214469-Are-my-coins-stored-securely-

Basically, the seed is randomly generated when you initialise the device... it is only ever contained within the device and the only time it is displayed is on the devices screen when you first set it up and confirm it.

It certainly isn't pre-programmed... and everytime you reset/wipe the device you generate a new seed.