I believe the movement/mobility/"running man" stat is some sort of internal unit like meters instead of a user-facing unit like tiles. Some examples:

My soldier has 12 mobility, but can move 8 linear spaces or 5 diagonal spaces.

An enemy is disoriented and the debuff applies a -6 mobility, the f1 screen lists their movement as 12-4.

This one specific to Spectrum Green. My Paladin-class soldier (gets +3 mobility passive) is listed as 15, but when I equip them with a -1 mobility weapon they list as 15-4.

How should I read and interpret this stat?