This package includes the following external libraries:

Eigen (http://eigen.tuxfamily.org)
License: MPL-2.0  (see inst/licenses/MPL-2.0.txt)
Copyright (C) 2006-2022 Eigen authors

ANN - Approximate Nearest Neighbor Library
(https://www.cs.umd.edu/~mount/ANN/)
License: LGPL-2.1-or-later  (see inst/licenses/LGPL-2.1.txt)
Upstream copyright notice: see inst/licenses/ANN-Copyright-Notice.txt
Copyright (C) 1997-2010 University of Maryland,
and Sunil Arya and David M. Mount

Spectra (https://spectralib.org/)
License: MPL-2.0  (see inst/licenses/MPL-2.0.txt)
Copyright (C) 2016-2023 Yixuan Qiu and other Spectra contributors