I just came back to the game with Deathwing. I noticed in the loading screen that some player names have a little blue symbol next to their name, looks like a little lightning bolt.
It is not the symbol that indicates they are in a party.
Just curious, thanks for the help.
It’s the Booster that increase Hero XP gains by 100% and gold gain by 150%, at the end of the match. You can eventualy buy them in the Collection / Boost tab of the menu.
That indicates that they have a Boost (equals with the old Stimpack, so extra gold and xp, the only difference that now it gramts a tiny bit to everyone (5%)).