The “range” of attack types was originally a proper variation of distance. Then, the design was changed, and it became little more than a way to vary the utility of troops — users began to favor smaller maps with denser variety of terrain, and the distances were condensed down to 1 tile (adjacent) for all attacks. Simplification was probably also a reason.
With the Ranged Attacks Mod by “4basedJake”, so–called multi-hex attacks were made available again on the WML framework: attacks with the ‘range’ type of "ranged" could be used to target enemies farther than 1 tile away from the source.
With the Uber Default Era by “Eagle11”, the concept of Ranged Attacks was implemented and expanded, but did not attend some of the underlying shortcomings (ahem).
This uses a more modular approach, allowing for the distances of multiple ‘range’ types to be defined. It uses pathfinding to determine line–of–sight. It also does not cause the distance to vary with the troop's ‘level’.
This bundle includes three modules: "ranged", "high", and "artillery".
See to its Help page for more information.