This is not the offical core and need to run in browser. The script can only be used to help getting the core but not the core itself!
yarn add b3procore
or
npm install b3procore
In your script
const {getCore} = require('b3procore')
// After editor start
const core = getCore();
Add scipt bellow under your user script description
// require https://unpkg.com/b3procore/dist/ProCore.js
And use getCore()
directly