A mustsee when doing TF autographs! Testflight signed source quote list...

Apple's TF signature is actually a way for iOS applications to be downloaded through Apple's official product TestFlight. The original intention of putting it on iOS was for Apple to use it for internal testing downloads of some APPs before they were released. Taobao, Zhihu, and even Alipay will use this method to provide some customers with distributed downloads before the official release to avoid irreparable problems after the official release. At present, many products will use tf as a distribution method before being put on the shelves due to difficulties in putting them on the shelves and long review weeks.
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