How can I alter a panel page variant provided by another module in my own module?
I am using Advanced Forum, and it provides a panel page to override Drupal's core forum display behavior and some variants: Top Level Forum, Container and Forum. But I have changed some layout options, and added a few more panes, and disabled some other panes etc in page manager UI. Now I want to export this into code, i.e. in my custom module. I can export the code using the export option in the UI, but I don't know how to add that code in my module. In other words I don't know which hook to implement to override this variant provided by Advanced Forum, instead of creating my own variant.
I know how to provide default panel pages or variants using
hook_ctools_plugin_directory(), but I couldn't find out how to alter an existing page variant provided by another module.
Is there a hook for that?