Function include_closure 

pub fn include_closure(
    seeds: Vec<PathBuf>,
    vendor: VendorTargets,
    extensions: &PhpFileExtensions,
) -> Vec<PathBuf>

Returns seeds plus every file reachable from them through require/include targets that resolve to a real file with a PHP extension in extensions, recursing since a newly-added file may itself reach further files. Only statically-resolvable target shapes are followed: a literal string, and __DIR__ / dirname(__FILE__) concatenated with a literal string, the common manual-bootstrap idiom (e.g. require_once __DIR__ . '/../legacy/bootstrap.php'). A bare literal with no __DIR__ resolves relative to the including file’s own directory.