: Open the Eaglercraft singleplayer menu, select your world, click "Backup" , and then select "Export EPK File" to save it to your device.

Creating a resource pack * To make a custom resource pack for your site, clone this repository and edit the files in lwjgl-rundir/ neon443/eaglercraft-1.5.2-Original - GitHub

: Unlike the standard Java Edition which stores worlds in folders on a hard drive, Eaglercraft stores world data in your browser's local storage. To back up progress or move a world to another device, players can export their worlds as EPK files and re-import them on different Eaglercraft sites. How to Use and Manage EPK Files

Managing these files generally involves the in-game menus or specialized developer tools. Importing and Exporting Worlds

For developers and players who want to create custom resource packs, the EPK format is essential. source code for eaglercraft 1.5.2 - GitHub

Players frequently use EPK files to share maps or save their progress across different computers.