The idea here is much the same as before. You add colour codes to a tab, and assign each colour as a group that you can name. But now, you can click on the tab group to collapse all the tabs in that group into one. To expand them, just click on the group again. You’re also free to drag and move the tab group around as if it was an individual tab.

This feature is part of the wider Chrome 85 update. Other improvements brought by the update include the ability to preview tabs by hovering your mouse pointer over it before you click it. Beyond that, the update also promises 10% faster loading, as well as the ability to share URLs using QR codes. The announcement post on the Google blog was dated 25 August. Which means that the update should already be available. (Source: Google)

Google Chrome Tab Grouping Now Available  Also Allows Collapsing - 2