How to Import a Converted .mrpack ZIP into ATLauncher
ATLauncher does support .mrpack natively, but the converted ZIP route is sometimes faster — especially if you have already done the conversion for another launcher.
Steps
Open ATLauncher and click "Create Pack"
Choose Minecraft version and loader.
Locate the instance folder
Right-click the new pack → Open Folder.
Drop in the ZIP contents
Extract the converted ZIP into the instance folder.
Launch and verify