Revise privacy policy
Reference must be made to the back-translation of an input by DeepL. For this purpose, it is sufficient to refer to the anonymity of the text and the privacy policy of DeepL: https://www.deepl.com/de/privacy
"When you use our translation service, you only enter texts that you want to transfer to our servers. The transmission of these texts is necessary for us to perform the translation and provide you with our service. We process your texts, the documents you upload, and their translations for a limited period of time to train and improve our neural networks and translation algorithms."
Point out that the DeepL service is involved only when the "Check text" button is clicked.