RePack
Open any Eaglercraft world, tweak what you want, and export it back. Runs entirely in your browser — nothing leaves your device.
These browser bookmarks let you grab EPK files straight from an Eaglercraft page and open them here automatically — no manual download needed.
Drag this to your bookmarks bar. Click it on any Eaglercraft 1.12.2 client page to extract the world EPK and open it here.
The idea: inject a bookmarklet on an active Eaglercraft tab that reads the cached/IndexedDB world data while you're in-game, sends it to RePack, and writes edits back.