Constant META_OIDC_AUDIENCE 

pub const META_OIDC_AUDIENCE: &str = "oidc_audience";

Records the OIDC audience (aud:) value of an id_tokens: entry on an Identity node. GitLab CI emits one Identity per id_tokens: key; the audience is what trades for downstream cloud creds (Vault path, AWS role, etc), so audience reuse across MR-context and protected-context jobs is the precise privilege-overscope signal. Set by the GitLab parser.