DefaultBuiltinConfig: [
    {
        assumePrimitive: true;
        names: [
            "NULL",
            "NA",
            "NaN",
            "NA_integer_",
            "NA_real_",
            "NA_complex_",
            "NA_character_",
        ];
        type: "constant";
        value: null;
    },
    {
        assumePrimitive: true;
        names: ["TRUE", "T"];
        type: "constant";
        value: true;
    },
    {
        assumePrimitive: true;
        names: ["FALSE", "F"];
        type: "constant";
        value: false;
    },
] = ...

Contains the built-in definitions recognized by flowR