Tilemap Json/TMX Open / Export

The tilemap features in Aseprite 1.3 make it perfect for editing and compressing tilesets, but there’s no way to open or export the tilemap as a .json (or .tmx for Tiled compatibility) file, which is what is needed to use in any project, meaning that I would have to export the tileset only and then redraw my tilemap from scratch on Tiled or some other tool.

This thread suggest to use a script, but ideally it would be perfect if we could just open / export tilemaps from .json (or .tmx) files.