I like the idea behind this addon, but many things don't work for me.
1. When I click the blockchair icon on the FF toolbar:
a. "Popular coins" is always selected, it doesn't remember my last choice
b. The loading animation on "Popular coins" just plays forever, it never loads any coins
c. If I choose "My portfolio", the loading animation disappears, but no coins load. I have selected the "Manage Portfolio" link and added the coins I want to see, but they never show up in the addon.
d. The "What to show in the Extension badge" drop down menu is empty, I assume it is supposed to have something?
e. The two options further down shouldn't be shown every time you click the addon icon, they should be hidden somewhere. This isn't great UI.

2. The addon looks for crypto address/transactions on the current page and hyperlinks them to blockchair.com. I understand why, but this should be configurable - many sites I use already have a link on these addresses, and I want to go to where the site is pointing me. It would be great if the addon respected the original anchor, and if the user clicks the little blockchair icon that you insert on the page, THEN it takes you to blockchair, but otherwise it goes to wherever the original link goes. Ideally we should be able to also disable this hyperlinking if we want. Then if I want blockchair to look up an address or transaction I can just right click it and choose blockchair (as is currently available).

Happy to re-rate once these things are fixed.
I'm currently running FF beta if this helps 86.0b3