Official versions from F-Droid are built and signed by the repository to match the original source code, ensuring they haven't been tampered with.
You can find the specific modded file reported on platforms like APKadmin , which hosts user-uploaded content. Safety and Risks
While the official "b60" version refers to the v4.5 release of the app, "modded" versions are typically distributed through third-party hosting sites rather than official repositories like GitHub or F-Droid.
The original developer has stated that SAI is no longer under active development, though the installer functionality remains stable for older Android versions. Releases · Aefyr/SAI - GitHub