You probably stored your script(s) directly "in the node", or rather as an internal resource of the scene (when you open the .tscn
file in a text editor, you should see the code).
To save the script as file, open the scene, click on the node in question, then in the inspector, go to the "Script" property and click on the little arrow to the right of the script, where you can select "Save" to save it like any other resource in Godot.