This is a demonstration of using the Web Serial API to connect to a AIS receiver, such as the dAISy or dAISy 2+ receivers from https://wegmatt.com/.
It uses the OpenLayers API to draw the locations of nearby vessels on a map.
To try this out (for example on https://googlechromelabs.github.io/web-ais-viewer/), you'll need a fairly recent version of Chrome (M79 should work). On top of that this demo depends on a number of unreleased features, which means you'll need to turn on the Experimental Web Platform features flag at chrome://flags#enable-experimental-web-platform-features to enable both the Web Serial API as well as the experimental import map feature.
This is not an official Google product.