Can Threat Tracker be used with a Target Lock acquired from Targeting Synchronizer? To me it reads like it would fit the "game effect" example.
Some people have suggested, that the game effect is dependent on the first condition, i. e. attacking the ship at that point.
When a friendly ship at Range 1-2 is attacking a ship you have locked, the friendly ship treats the 'ATTACK (TARGET LOCK):' header as 'ATTACK:'. If a game effect instructs that ship to spend a target lock, it may spend your target lock instead.
FAQ:
If an enemy ship is locked by a friendly ship equipped with Targeting Synchronizer, the friendly ship grants friendly ships that are attacking the enemy ship the ability to treat the "Attack (Target Lock):" as "Attack:" but does not alter any costs (such as spending a target lock). (X-Wing FAQ, Version 4.4.0, Updated 10/25/2017)
If an enemy ship is locked by a friendly ship equipped with Targeting Synchronizer, although a friendly ship may not actually have the target lock, it can spend the target lock from the ship with Targeting Synchronizer as though it did. (X-Wing FAQ, Version 4.4.0, Updated 10/25/2017)
Q: What are examples of game effects that instruct a player to spend a target lock? A: The cost for a secondary weapon such as Proton Torpedoes, using pilot abilities like Lieutenant Colzet, or spending a target lock during the "Modify Attack Dice" step to reroll attack dice are all examples of spending a target lock. Removing a target lock or assigning a blue target lock token to another ship are not examples of spending a target lock.