The package seems to have changed a bit and now on top of the usual medal, decals and x5 tokens you get to choose two out of five options inside the package. The options you get to choose two of are a 10 day rental of T-34-85M, M48A2 Räumpanzer, Chrysler K, T-54 first prototype and a bundle of 5 x5 tokens and 10 universal fragments. You choose what you want ingame in the depot.
The system explained better and with pictures in the newspost:
Or if you prefer it in a video instead:
Source: https://www.reddit.com/r/WorldofTanks/comments/h7pope/twitch_care_package_june_available/