When I open my spreadsheet and choose Tools > Script editor, the list shows five script projects. They contain onEdit() simple triggers and onChange() installable triggers.
How do I know which copy of these functions runs when the user edits the spreadsheet?
If you have multiple copies of a simple trigger function like onEdit() in the same script project, only one of them will be active. Specifically, it will be the one that was declared last. If there are multiple script files in the same project, they are evaluated in the order they appear in the left-hand file list pane, or alphabetically, depending on whether you are using the new Chrome V8 script runtime or the legacy Rhino runtime.
If you have the same simple trigger like onEdit() in multiple script projects that are each bound to the same spreadsheet file, every copy will be active.
Installable triggers are created separately for each script project. To determine which installable triggers are active, open each script project in turn and click the clock icon in the left-hand tool pane.