It recently came to my attention that there are two very similar named specs, and we have a mixture of both in here 🤦‍♂️. We could just say that this library covers both of them... but they do kinda have separate concerns:

https://www.w3.org/TR/cssom-1/

CSSOM defines APIs (including generic parsing and serialization rules) for Media Queries, Selectors, and of course CSS itself.

https://www.w3.org/TR/cssom-view-1/

The APIs introduced by this specification provide authors with a way to inspect and manipulate the visual view of a document. This includes getting the position of element layout boxes, obtaining the width of the viewport through script, and also scrolling an element.