Edmonlytica is a proof of concept for making your own digital analytics stream using GTM Server Side and BigQuery. See the blog post for details: https://code.markedmondson.me/edmondlytica/
This is the browser tag to be imported into GTM Browser Side. It works in conjunction with the Edmonlytica GTM Server Side Client and the Edmonlytica GTM Server Side Tag, which need to be installed as well to work.
This gathers data from your GTM dataLayer and sends it to the /edmonlytica ednpoint, which is intended to be your GTM Server Side client.