mbed-os/tools/test/config_test/test09/lib1/lib2/mbed_lib.json

{
    "name": "lib2",
    "config": {
        "p1": "v_p1_lib2",
        "p2": "v_p2_lib2"
    },
    "target_overrides": {
        "b1_label": {
            "p1": "v_p1_lib2[b1_label]",
            "p2": "v_p2_lib2[b1_label]"
        },
        "b2_label": {
            "p1": "v_p1_lib2[b2_label]",
            "p2": "v_p2_lib2[b2_label]"
        }
    }
}