How do you use TinyDash or any of the Web Bluetooth examples on the Espruino Hub www with Puck.js through the Pi

Ahh - so running a web browser (Chrome hopefully) on the Raspberry Pi itself?

I believe you just need to go to chrome://flags and turn on Experimental Web Platform Features and restart.

However the idea of the MQTT bridge is not to need Web Bluetooth, and to allow you to view the webpage on any device while using the Raspberry Pi as the bridge.

There's a bit of an example here:

https://github.com/espruino/EspruinoHub/­blob/master/www/rssi.html

You should just be able to check on the /ble/advertise/ BLE topic and extract any data (eg the meter reading) that you want...