Function diff_hygiene_with 

pub fn diff_hygiene_with(
    diff: &str,
    vendored_globs: &[String],
) -> Vec<HygieneIssue>

diff_hygiene with explicit vendored globs (from .prbot.toml); an empty slice means DEFAULT_VENDORED_DIRS.

Vendoring is why this split exists. A PR that adds 265 files of upstream source under thirdparty/ is doing the thing it says on the tin: every class-D signal fires (bulk added files, files over the line threshold, sometimes binaries), and every one of those findings is wrong — the suggested remedy, “.gitignore or exclude it”, is impossible for source you must compile. Suppressing the class inside vendored paths is the whole fix; the reviewer’s judgment about vendored code belongs in the prompt, not here.