This particular code looks fairly straightforward (could definitely be clearer). It's building a url and including the email as a path segment. What the remote service (http://tokendispenser-yeriomin.rhcloud.com/) is doing with that email is harder to determine.

That part is open source too: https://github.com/yeriomin/token-dispenser

That said, if you're sketched out by it, don't use it on a Google account with any data on it. Just make a new empty account for apk downloading.

"Stores email-password pairs, gives out Google Play Store tokens"

I couldn't tell if it was encrypting the password but even if it was... yuck!