Here is ChatGPT’s attempt at the open bounty:``` Maximally localized Wannier functions (MLWFs) are a set of functions that are obtained by localizing the Bloch functions in a crystal. They are widely used in solid-state physics to study the electronic properties of materials.

One of the key properties of MLWFs is that they are supposed to be real functions. This is because the MLWFs are designed to represent the localized electron density in the crystal. The electron density is a physical quantity that is always real, so it makes sense for the MLWFs to also be real.