It means changing words drawn in a game's own typeface inside a finished screenshot — without touching the game and without owning the font. The model samples the lettering already in the image (glyph shapes, weight, spacing, fill gradient, outline, shadow and even compression softness), removes the old characters and draws the new ones with the same properties. The rest of the frame stays as captured.
Game typography is often a commissioned display face that was never released, with bevels and outlines applied by the engine at draw time, so the manual route — identify, license, rebuild the effects — rarely works.