It is absolutely ridiculous that there are no tiny text editors for Android that are FOSS and ad-less. Let's change that.

Simply find a text file to open, and open it with Gratis. Once you have finished editing the file, click the back button and pick a save location. If you do not wish to save it, simply click the back button again without choosing a save location to quit without saving. This is as simple as it gets; perfect for changing a value in a config file or fixing a bug in a script.