Twilight's Fall – a separate game. Twilight Imperium's expansions, mods and rules topics are not part of it.

Mercenaries

At the start of a space combat, you may remove up to 2 fighters you control in a system adjacent to the active system. Then, choose 1 player participating in that combat; that player places the same number of fighters from their reinforcements in the active system.
Florzen ProfiteersFaction ability

At the start of a space combat, you may remove up to 2 fighters you control in a system adjacent to the active system. Then, choose 1 player participating in that combat; that player places the same number of fighters from their reinforcements in the active system.

Source: Discordant Stars