Tinderbox 7 uses “Taskpaper” in these prototypes, although the actual name of the app is “TaskPaper”. The Taskpaper (sic) import process could be improved. TaskPaper “due” tags could be parsed into $DueDate since TaskPaper uses a consistent format for the tag:
@due(2017-10-11)
Also, notes added to projects or tasks in TaskPaper are not imported as the $Text for that project or task, but as separate Notes in Tinderbox.
TaskPaper has very robust AppleScript support and many contributed scripts – including export to OPML.
I personally prefer to use OPML export from apps that support it (or can support it with custom scripts) and then import that OPML to Tinderbox – since this gives me the greatest control on how data is imported and parsed to built-in and User attributes.