Hi guoc,
many thanks for the app. It's doing a great job. As I see it from my point of view it complements what ZotFile for Zotero is doing. Especially useful is the option to extract all annotations using the macOS service menu and then saves every single highlight and note in a separate markup file.
Only it throws an error. Once I found out what it exactly is I'll let you know.
Again, thanks.
wolf