I've just released Mp3tag for Mac v1.8.1 with the following changes:
New
• Added scripting function fmtDuration to create a formatted duration string based on numerical input.
• Added function SayDuration to Web Sources Framework
• Added JSON-related function json_select_many_count to Web Sources Framework
• Added JSON-related function json_foreach_counter to Web Sources Framework
• Added JSON-related function json_foreach_reverse to Web Sources Framework
Changed, Improved & Fixed
• Extended json_select_many with optional parameters for last item separator and max items to select
It's a free update! You can update the Mac App Store version via the Update tab in the App Store app and the standalone version from within the app via File → Check for Updates .