Quetzal is a standardised file format for the saved state of Z-machine games, invented by Martin Frost. Prior to the introduction of Quetzal, each Z-machine interpreter saved games in its own format; Quetzal enabled players to begin a game on one architecture (for example, a pocket computer) and end it on another. Use of the format is strongly recommended in Graham Nelson's Z-machine standards document, but not obligatory. Most modern Z-machines have the ability to save Quetzal files.
The format's name is a backronym for "Quetzal Unifies Efficiently The Z-Machine Archive Language".