Why id is a part of attributes object

[antonkomarev]

Project.find('1').then(project => {
    console.log(project.attributes()); // { id: '1', name: 'test' }
});

Why id key is a part of the attributes?

[nicklandgrebe]

This library was not designed with only JSON:API in mind, JSON:API is only the starting point and many other standards may consider ID to be an attribute