In this appendix we explain the structure of the Officer Ability tree, and what the various custom new abilities in it do.
The general structure of the ability tree is somewhat inspired by shiremct's celebrated "Proficiency" system. Each training level grants some "free abilities", and grants a choice of one ability out of two. This choice is final, it's impossible to redo it (well, almost impossible), and it's impossible to pick both in the same level. All abilities don't break individual concealment, but some may not be used in squad concealment. In addition, most abilities have some scaling with the officer's rank. Most abilities numbers are open to config, see XComGameData_SoldierSkills. Also, most abilities, including passive auras, are disabled by being impaired in some way, and an impaired user cannot receive the bonus from those auras. Some of it can be configured.

Data - a focus mechanic used by these abilities. It doesn't come with a fancy bar (like base game Templars, proficiency faction classes, and others), because then this bar won't show on those classes. You can see your current data balance at the end of the Command's ability description in a mission.
Command Range - a dynamic radius around the officer in which certain passive auras work. The range scales with officer rank - 7/9/11/13 tiles around the officer. If any ability that uses Command range is given to someone who's not an officer, a default value of 10 is used instead.

• Battlefield Analysis - so called "focus" mechanic. Grants 1 point of "data" every turn, up to a maximum of 5. Each point of data increases the aim and defense of all soldiers within Command Range by 1. When the data is full, it can all be expanded for a Command.
  
• Command - grants one action point to a squadmate within visual range. Consumes all Data.
  
• We Can Make It - when carrying out bleeding out units, gain +5 mobility.

• Officer's Toolkit - Grants a free flashbang, free smoke grenade, an extra utility slot, and the Patch Up ability. Patch Up allows healing an adjacent ally for 2HP, and can be used 3 times (also removes bleeding).
  
• Battlefield Survey - start missions concealed, and don't lose concealment when the squad does. Reduced detection radius of this unit. Can reconceal up to 3 times during the mission, by paying strategic cost that increases after every use. Entering concealment with this ability ends the turn. Also extends vision range of this soldier by 5.

• Buy Time- spend strategic resources to extend the timer on the given mission.
  
• Oscar Mike - An activated ability to boost the mobility of all allies within Command Range by 5 for one turn. The ability starts with 1 charge, and gains one charge with each additional officer rank. The ability has a 5 turn cooldown, and this is decreased by 1 for each officer level. This ability costs 2 Data.
  
• Fast Analysis - Data gathering starts at 1 point higher, and when using Command, it will reset to 1 and not to 0.
  
• Quick Observation - Free action to increase Data value by 1. This ability starts with 1 charge, and it increases by an additional 1 for each Officer rank.

• Defilade - Passive aura: allies within Command Range gain additional 5 defense while in cover. Also reduces incoming damage against allies within Command Range by 1.
  
• Get Some - activated ability to increase crit stat of all squadmates within Command Range by 30. The ability has 6 turns cooldown, that's decreased by 1 with each Officer rank.

• Emergency Command - the same as Command, but it's not tied to the Data system. One charge per mission.
  
• Revitalize Ally - reduce cooldown of all abilities of an ally of your choice by 3. This ability costs 3 Data. It starts with 1 charge, and gains one extra charge in the next Officer level. Free action.
  
• Second In Command - if this soldier has a level 2 or higher bondmate, then this bondmate becomes Second In Command. This grants the following two abilities:
  
  • Take A Look At This - the bondmate can increase the Officer's Data value to 5. One charge per mission.
    
  • Assume Command - if the officer dies, their bondmate gets one turn immunity against mental effects, and they inherit the Officer's Battlefield Analysis and Command abilities, starting with a full Data bar (so Command can be used right away). This lasts only for the duration of that mission. If this ability triggers, if the bondmate is sent to officer training, they will train faster than usual.

• Fire Discipline - passive aura. All allies within Command Range gain +20 aim while overwatching.
  
• Focus Fire - target an enemy. This enemy loses one point of armor, and squadmates attacking this enemy gain cumulative +5 aim.

• Combined Arms - all soldiers within Command Range deal +1 damage with all attacks.

• Rope Mastery - grants a grappling gun, an ability to pull allies towards the officer, and the Have A Spare ability, which allows the officer to spend one ammo point to restore one ammo point to an adjacent ally. In addition, using Have A Spare, or Patch Up grants a movement only action point to the user.
  
• Lead By Example - passive aura effect: all allies within Command Range have their aim, will, hacking, and dodge increase by half the difference between the Officer's value of that stat, and theirs, assuming it's positive (so Officer with 90 aim will add +10 aim to a soldier with 70 aim, but will not harm a soldier with 92 aim).