A lot of identical staff in Comsol material database?

I got a lot of elements in Material Browser of Comsol Multiphysics of Optics section. Unfortunately, all data looks identical and similar to stub.

Each element has the same expression, which can be seen on screenshot.

How this should be used?

In your particular case, the real and imaginary parts of the refractive index are functions defined from n_interp and k_interp, which usually denote the interpolated values (either supplied by COMSOL or user-supplied). In many simulations, you might need the refractive index to be a continuous (and maybe even differentiable function); thus, some modeling from a discrete material properties data is needed. The underlying sampled data (n_interp and k_interp) is likely different and comes from different sources for different materials.