It goes beyond one-liners. This is especially apparent in sysres.c, where not only are the function names identical, they appear in the same order. There's also non-trivial functions, that are obviously copied line-by-line, with some modifications. See KepGetSystemResource for example.

While I guess there's no proof that WinuxOS and ExectOS share the same authors (aside from identical first and last name), this ReactOS pull request was certainly done by the same person: https://github.com/reactos/reactos/pull/2853#issuecomment-65...