Whenever you need to copy the exact WP RSS Aggregator settings from one site to another, or if you want to export a copy of the settings for some other purpose, you can use the Import/Export features available at RSS Aggregator > Tools > Import and at RSS Aggregator > Tools > Export.
This is a one-click action. Simply visit the page, click on the Export Settings button, and you'll see a JSON file being downloaded.
Likewise, this is also a very simple process. Simply visit the Import tab in the Tools section, click on the Browse button to find and select the JSON file you would have exported as shown above, and then click on the Import Settings button.
Once you do that, the WP RSS Aggregator settings from the JSON file will be applied to the plugin.