bigcurve is released under the MIT licence (see LICENSE).

The refinement test in src/bigcurve.h (perpendicular projected distance,
the midpoint-near-an-end check, the forced split of arcs wider than 30
degrees and the maximum depth of 16) is a port of resampleLineTo() in
src/projection/resample.js of d3-geo, https://github.com/d3/d3-geo,
distributed under the following licence:

Copyright 2010-2024 Mike Bostock

Permission to use, copy, modify, and/or distribute this software for any purpose
with or without fee is hereby granted, provided that the above copyright notice
and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
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TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
THIS SOFTWARE.
