espocrm-base/application/Espo/Resources/metadata/fields/bool.json

{
    "params": [
        {
            "name": "default",
            "type": "bool"
        },
        {
            "name": "audited",
            "type": "bool"
        },
        {
            "name": "readOnly",
            "type": "bool"
        },
        {
            "name": "readOnlyAfterCreate",
            "type": "bool"
        }
    ],
    "filter": true,
    "fieldDefs": {
        "notNull": true
    },
    "default": false
}