Import Annotations via json file

I used the app Book Reader https://f-droid.org/en/packages/com.github.axet.bookreader/ and switched to FBReader, because it also has a macos app and a way to synch between devices. But all my annotations got lost in the transition from Book Reader to FBReader. I found out that Book Reader used json files for annotations. Is there a way to import these to the books in FBreader? Here is an exemplary json file with annotations: Make-Capitalism-History.json