Thanks. Where you refer to "the editor" is that your own tool or a Playdate development thing?
It's a custom tool I've written myself, specifically for Melkhior's Tower. It's a Windows application written in C#/Monogame. There's more info about it in this previous post: https://bitglint.itch.io/melkhiors-tower-playdate/devlog/1326794/map-editor