In context: Since AMD made its FidelityFX Super Resolution (FSR) 2.0 upscaling technology open source, modders have devised methods of manually adding it to games that feature Nvidia's competing DLSS. Though not perfect, the mods offer drastic performance and visual improvements for users who don't have Nvidia RTX graphics cards.
After modders added FSR 2.0 to Cyberpunk 2077 by replacing the game's DLSS implementation, they theorized the same was possible for any recent title that includes DLSS.
That theory is now bearing out, with AMD's upscaler working in Death Stranding, Red Dead Redemption 2, Marvel's Guardians of the Galaxy, Metro Exodus: Enhanced Edition, Dying Light 2, Horizon Zero Dawn, and Control.
Currently, the mod needs to be customized for each game, but the builders of the Cyberpunk version are developing a universal mod. Users install them by replacing some of the DLSS files with modified FSR files, then activating DLSS in the in-game menu.
Initially, modding Cyberpunk only offered one FSR quality setting, but multiple resolutions are available for Dying Light 2 and Death Stranding. In the latter game, tests show benefits most acute for 4K but considerably drop off at 1080p. The developer behind the Red Dead version warns that using it online could get you banned and that it doesn't work through Vulkan.
It would still be better if the developers of these games officially added FSR 2.0, as these mods have some bugs. However, the mods prove that official implementation might not be that difficult.