Comment by tadfisher
> Why are these variables needed for this entire tooling?
They are not. The Github API secret key should never be exposed in the environment, period; you're supposed to keep the key in an HSM and only use it to sign the per-repo access token. Per the GH docs [0]:
> The private key is the single most valuable secret for a GitHub App. Consider storing the key in a key vault, such as Azure Key Vault, and making it sign-only. This helps ensure that you can't lose the private key. Once the private key is uploaded to the key vault, it can never be read from there. It can only be used to sign things, and access to the private key is determined by your infrastructure rules.
> Alternatively, you can store the key as an environment variable. This is not as strong as storing the key in a key vault. If an attacker gains access to the environment, they can read the private key and gain persistent authentication as the GitHub App.
[0]: https://docs.github.com/en/apps/creating-github-apps/authent...
Environment variables used to be standard practice for API keys. It seems like every time someone finds a way to get a key, standard practice gets more convoluted.