In February 2018, my team at Mozilla released a WebVR exporter for Unity to let people build their experiences and games in Unity but still being able to target the web.
After a while the WebVR API was deprecated and the new WebXR API was officially released in December 2020.
We started working on upgrading the exporter to support this new API and in April 2020 we released a new version of the exported.
Apart from the API refresh itself, we included a bunch of upgrades on it, like moving away from the legacy renderer to the Universal Render Pipeline (URP), or upgrading the input system.
You can find the code in our github repository, try a demo online, or download the asset directly from the Unity Assets Store.