Which action is triggered when a theme was modified?

I want to intercept plugin changes, but no action hook listed in the Action Reference seems to do it. I tried after_switch_theme which is triggered only after changing from one theme to another, and load_themes.php which is triggered when entering the “Appearance” page with the list of currently installed plugins.

Which action will be triggered after configuring a theme in customizer?
Which action will be triggered when a file of a child theme is modified?
Which action will be triggered when a theme was updated to a newer version?