sh/tmpfiles.sh.in has only a copyright notice, but no license notice: # Copyright (c) 2012 Gentoo Foundation # # This instance based on the Arch Linux version: # http://projects.archlinux.org/initscripts.git/tree/arch-tmpfiles # As of 2012/01/01 The Arch Linux version seems to be licensed under the GPL, according to the PKGBUILD file in their repository. Sole author (up to 2012-01-01) is Dave Reisner <dreisner@archlinux.org>, according to their git log. So, please add a GPL license notice to the file and include a copy of the GPL with OpenRC's tarball. Alternatively, you could ask the author if the file can be relicensed under 2-clause BSD.
As the original author of that code, it's now released under 2-clause BSD