Source code at:

• https://github.com/ag-grid/ag-grid-docs/blob/master/src/example.php
• https://github.com/ag-grid/ag-grid-docs/blob/master/src/example.js

This example appears to use client-side data, so it doesn't demonstrate server-side row models at all.

How did they color the monthly breakdown cells?

        cellClassRules: {
            'good-score': 'typeof x === "number" && x > 50000',
            'bad-score': 'typeof x === "number" && x < 10000'
        },