OpenEquivariance [1] is another good baseline for with kernels for the Clebsch-Gordon tensor product and convolution, and it is fully open source. Both kernel implementations have been successfully implemented into existing machine learning interatomic potentials, e.g. [2,3].
[1] https://github.com/PASSIONLab/OpenEquivariance
[2] https://arxiv.org/abs/2504.16068
[3] https://arxiv.org/abs/2508.16067