There several reasons why PRs cannot have (public) previews:
- The PR did not affect any relevant files (e.g. non-spec files in
`aio/` or `packages/`).
- The PR cannot be automatically verified as "trusted" (based on its
author or labels).
Note:
The endpoint does not check whether there currently is a (public)
preview for the specified PR; only whether there can be one.
PR Close#25671