OptionalentropyMust at least be 20 and at most 199.
The prefix of the token without the underscore at the end. Prefer short prefixes. Can only contain chars a-zA-Z0-9_. Must not end with _.
See which prefixes GitHub uses:
https://github.blog/2021-04-05-behind-githubs-new-authentication-token-formats/
Options for creating a new generator with createTokenGenerator.