...It supports filtering by suffixes or prefixes (for example, “Test.php”) to keep selection deterministic. Exclusion lists help you skip vendor directories, VCS folders, or generated artifacts that would otherwise slow down tools. The iterator interface means results are streamed rather than loaded at once, which keeps memory usage modest on large codebases. It also plays nicely with glob patterns and SPL iterators, so you can combine it with other filesystem utilities. As part of the PHPUnit tooling suite, it’s optimized for speed and predictable behavior across platforms.