Who made it, and why: author, credits, licence and support

The README says who wrote it and the two projects it was built for, WII6
and OGLAS, with their sites; credits Ground Control for the modem and
the library that does the protocol work; and gives the licence with
contact details, where to report issues and what helps in a report, and
that it is not a Ground Control product. The licence, every source file
and the Python package's metadata carry the copyright and email; the
package lists its homepage, repository, issues and changelog.

src/rb9704_worker.c

@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: MIT
+ * Copyright (c) 2026 Scott Penrose <scottp@dd.com.au>
  *
  * rb9704_worker.c - the one thread that calls into Ground Control's library.
  *