Undocumented functions glob0() and glob1() were just helpers for glob.iglob(). They are not underscored because the glob module has __all__. They survived numerous refactorings only because they were used in the msilib module and some MSI related scripts. But the msilib module and these scripts have been removed.

glob1(root_dir, pattern) is equivalent to iglob1(os.path.join(glob.escape(root_dir), pattern)), but more restricted and slightly faster, because it does not need to escape root_dir and process the result.

Other alternative is iglob(pattern, root_dir=root_dir), which can even be faster, but it emits paths relative to root_dir. You can use (os.path.join(root_dir, p) for p in iglob(pattern, root_dir=root_dir)) if you need to append root_dir. Actually, creating an efficient replacement of glob1() was one of purposes of root_dir.

glob0(root_dir, name) just checks that os.path.join(root_dir, name) exists. I did not see its use in third-party code.

Linked PRs

• GH-117337: Deprecate glob.glob0() and glob.glob1(). #117371