9.2 Terminology
Requester. The program that wants a file chosen, and which started the chooser. §9.1
Chooser. The program that shows the person's folders and answers with the file they choose. §9.1
Line. One message on the choosing channel: a single compact JSON object, encoded as UTF-8, followed by a line feed (U+000A). §9.3
Request. The first line the requester sends: everything the chooser is told about what is wanted. §9.4
Answer. The one line the chooser sends: the path chosen, or that nothing was. §9.5
Mode. Whether an existing file is to be opened (open) or a place
and a name to be saved to (save). §9.4
Filter. A kind of file the requester offers, named for the person and given as a list of extensions. §9.4