tckmap, stat_vox & stat_tck meaning

Dear experts,

I am trying to create Track-weighted FA image.
I created an image via
‘tckmap {input_tck -vox 1 -contrast scalar_map -image {fa_image} -stat_vox mean {fa_output_file} -force’

As I understood, this code leads to an image that is computed by -stat_vox mean and -stat_tck mean.

I am unclear what stat_tck mean would do.
Does it mean that my image will calculate mean FA along the total streamline? or it will calculate mean FA value within a voxel?

Thank you in advance