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and how can I deauthorize them?

Check this article. Let me know if you find how to remove minnowbooster.

https://steemit.com/esteem-feedback/@gaman/removing-the-esteemapp-posting-authority

Perfect thanks!
Just for my understanding, what is exactly what steemapp do when is in myy athorization field at 50%?

Yes that was my fear too, but idk why it shows 50%. I checked other uses that did not authorize anybody, they are getting same rewards as us. So basically we are not losing money.

I just want to prevent them from posting/upvoting on my behalf. I will ask them on discord chat.

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