There won't be a browser version at the moment, maybe at some point later. There are no other data sources only Coingecko because it is free. Everyone else, like CMC, wants registration or money.
It's a waste of time and there is no need for releasing browser version because Coingecko already has it's portfolio page that can be used right now and I think they also have multiple chart including tradingview.
Coingecko portfolio can be used with any browser including Firefox, Chrome and all other forks.
One more thing that could be considered is making a mobile version for Crypto Tracker but this needs much more development and there are good alternatives like Delta and FTX.