I migrated from Oneplus 3(Chinese android phone) to Galaxy Note 8 via Cloneit, since Samsung's stock migration tool didn't support Oneplus 3.
However, apps migrated(or preferably, cloned) on my new phone are recognized as 'app installed from unknown source' instead of 'installed from Google Play'.
It seems that Cloneit, the migration tool brought all apk files via connection and that's making all apps recognized as unknown source.
* So, I want to change their source property from unknown to installed from Google Play. *
My speculation is pretty pessimistic since it sounds like it's related to some security issues but I'm hoping some Superuser has an answer for this.