Source code: https://github.com/cp2k/cp2k

Short description: CP2K is an open-source package for atomistic simulations and electronic-structure calculations in molecular and condensed-matter systems. Its Quickstep module combines Gaussian basis sets with auxiliary plane waves through the GPW and GAPW methods. CP2K integrates the Wannier90 v4 library for direct, in-process disentanglement and localization. It provides physical AO-based and hybrid initial projections, automated comparison of localization trials, energy-window selection, and export of optimized Wannier Hamiltonians and transformation matrices. Both direct library integration and the traditional file-based interface support workflows using symmetry-reconstructed SCF orbitals.