This node lets you append something from a different blend file. You can choose the type of data you want to append on the node.
Path: The path of the blend file you want to import. If you want to include this file with your addon, add it as an asset
Name: The name of the data that you want to append. If you for example want to append a node group, this would be the name of that group in the other file
Linked: If the item should be linked from the other file or not
Appended: The data you appended from the file