rcsdiff(1) on OpenBSD
The text 28f5838c7758, as OpenBSD 3.8, OpenBSD 3.7, OpenBSD 3.6, OpenBSD 3.5, OpenBSD 3.4, OpenBSD 3.3, OpenBSD 3.2, OpenBSD 3.1, OpenBSD 3.0, OpenBSD 2.9, OpenBSD 2.8, OpenBSD 2.7, OpenBSD 2.6, OpenBSD 2.5, OpenBSD 2.4, OpenBSD 2.3, OpenBSD 2.2, OpenBSD 2.1 shipped it.
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