Belle Nuit Relation was written for MacOS 10.15 Catalina and runs with 64bit. It may work with older OS but is not tested.
The application is about 23 MB. You can just drag it into the Applications folder.
The application can read and write .csv and .txt (tab separated) files encoded UTF-8, Latin1, Windows Latin1 and MacRoman.
The handling of .json files is experimental.
The application writes .csv, .json, .txt and .html files, all encoded in UTF-8.
The application producers no other files than these explicitely created with write or saved by the user.