A TIL file is an archive that contains textures used by CTGP Revolution (CTGP-R), a fan-made mod to Mario Kart Wii that adds extra features, like new tracks and game modes. It stores a collection of graphics referenced in CTGP-R, which includes buttons, menu option titles, and icons.

You will only encounter TIL files if you download the CTGP-R mod and dig around the resource files packaged with it. The file is not meant to be manually opened by users. Instead, it is referenced by the Wii or Wii U console to load resources for menus and in-game graphics. However, some users looking to modify the appearance of the CTGP-R menu will manually open a TIL file to alter the textures stored within it. After making their changes, they will package the textures back into the TIL archive in the CTGP-R mod, transfer it to an SD card, and insert the SD card in the Wii or Wii U to play the mod. The user must have a valid copy of Mario Kart Wii to play the mod.