We have this warning:

⚠ push-to-pull-request-branch: target: "*" requires that all PR branches are fetched at checkout.
Your checkout configuration does not include a wildcard fetch pattern (e.g., fetch: ["*"]).
Without this the agent may fail to access PR branches when pushing.

Really, this warning is only needed in private/internal repos, as workflows can always access all code in OSS repos.

Most of our compilation is independent of public/private, but in the case of this warning message I think it's OK to condition the warning message on public status, if it can be determined.