The Manifest editor option is part of the new Manifest & resource options in App Cloner 2.3, which can be unlocked by purchasing the Manifest & resource options add-on. It should only be used if you are an Android developer or otherwise familiar with Android manifest files.
Misconfiguring an app’s manifest could break the cloned app’s installation or cause the app to crash.
The XML code editor offers code highlighting and also validates the XML document before returning. If you made a mistake, you can use the undo button in the toolbar to revert your changes. The undo / redo change history is only kept for the duration of the code editor session.
A search bar at the bottom allows you to find & highlight text inside the XML file.
If you have the small donation, you may import or export the XML file using the menu items Load file and Save file. The menu item Restore file allows reverting the entire file to its original version.
Note that all code editor changes are saved as patches in standard diff format. This is important in case the original app gets updated and the XML file is modified. Unless the two changes result in a conflict, e.g. a change that affects the same line, your changes will be merged with the changes from the updated app and applied to the resulting XML file. Should there be a conflict you may open the code editor and view or copy the patch file.