"Marines" and "AttFromNonNative" is gone.See patch #4683
The "Marines" unit type flag and the "AttFromNonNative" unit class flag has moved to the ruleset. They get meaning from action enablers. You can now control if/when "Attack" and "Conquer Unit" can be done with respect to tile nativity/livability. You also control their help text.
Ideas:
Have your "act from non native" flags control all attacks, caravan actions and spy actions. (Change the help text from "Attack" to "act" or something like that)
You can give a unit the ability to attack and conquer cities from a non native tile when its owner researches a special tech.
You can give special act from non native tile ability to certain nations (think Vikings).
Auto attack blocking unit type flags.See bug #25233
Enabling the autoattack server setting makes a unit attack other units that moves to an adjacent tile if certain conditions are met. In Freeciv 2.6 a hard coded rule prevented units with the "Nuclear" unit type flag from auto attacking. You can now decide what utype flag(s) will block a unit from auto attacking via game.ruleset's new auto_attack.will_never setting. An autoattack still won't result in a nuclear detonation.
Example: forbid both "Nuclear" and "GameLoss" units from autoattacking.
This effect type can be used to give attack bonus when specific player attacks. That was not possible with negative Defend_Bonus as its player requirements are about defending player.
Rulesets that are part of freeciv distribution are kept in sync with the development. Rulesets available as modpacks are only occasionally compatible with current development.