There's a GitHub provider for Terraform [1]. I tried it out on a GitHub Enterprise instance last year and found it a little awkward because they didn't have support for the latest GH APIs and the version before was missing a bunch of features. When I looked recently, they seemed to have got past that.

The principle is broadly the same as other Terraform workflows: import existing config and update it when you need to. You can manage repo permissions, people and teams, all centrally and in code. Super useful for tracking changes (the GH audit logs are a bit lacking in my experience) and identifying discrepancies between the expected and actual configurations.

[1] https://registry.terraform.io/providers/integrations/github/...