src/developer/ffx/plugins/emulator/data/config.json

{
    "emu": {
        "console": {
            "enabled": false
        },
        "device": "",
        "engine": "femu",
        "gpu": "auto",
        "instance_dir": "$DATA/emu/instances",
        "kvm_path": "/dev/kvm",
        "start": {
            "timeout": 60
        },
        "upscript": ""
    }
}