Indicator with aggregated volume for all the most actively traded bitcoin spot markets.
Can be denominated in either US dollars or the number of coins traded.
Can be displayed as stacked volume or an index that shows the percentage market share each market has.
In the settings you can exclude any market so that it only shows the individual and total volume of the markets you're interested in.
The currency it's traded against is always specified (e.g. USDT, BUSD, ...).
It's public and free for anyone to use.