The story
From a prompt in the PC version of the 2014 video game Call of Duty: Advanced Warfare which directs the player to press the F key to touch a fallen soldier's coffin during a funeral cutscene.
Etymology from Wiktionary, CC BY-SA 4.0.
press F to pay respects
Today it means: Used to convey that credit, recognition, or sympathy should be given. Full definition →