TEXT.TXT is a data file in Carmageddon and Carmageddon II. This file has part of the game's strings, so editing this will change the text that appears on screen. This file is crucial in order to translate either game.
The first line of the file contains the very first string, and after that, all strings are ordered, one per line. This means that the player can't swap two lines. Carmageddon's file has 245 lines, including the blank line at the end, and Carmageddon II's has 298, including the two blank lines at the end.
There are also some unused strings in both games, found in this file.