There are some rules involved:

Active Abilities will only be shown when they would normally appear in the Ability Container. This is controlled by Template.eAbilityIconBehaviorHUD. Set it to eAbilityIconBehavior_AlwaysShow for abilities that should also be shown, or eAbilityIconBehavior_NeverShow for those that should never be shown.

For active abilities that should be shown on the ability container but hidden in the summary (overwatch, hunker down), there's a way to hide it in config: Create a file called XComUI.ini and add the following lines to it:


Passive abilities are effects with display info. If the passive ability has an effect with infinite duration, make it responsible for showing with

Buffs and debuffs should be self-explanatory, they use the same path as passives except ePerkBuff_Passive is now ePerkBuff_Bonus or ePerkBuff_Penalty. X2StatusEffects.uc has numerous examples.

Primary weapons are only shown if the weapon has localization set up.
Secondary weapons are only shown if the weapon has localization set up or belongs to a known category. See this mod's ini file to see how that works.

Units can have a short help description that will be shown if the unit has it set up. To add it, add a line below strCharacterName in the localization file that looks like this: There also is an event you can use to override the string, see YAF1_UIUnitInfo.uc for details.