The library is
https://github.com/Rainrider/LibArtifactData-1.0
Me is me. I don't want to prevent using the library, I want to prevent somebody returning data instead of me.
Edit:
Maybe I still expressed myself unclear. I mean "me" like the person who wrote the lib, and "they" like the users. I ask myself what happens if some user decides to tamper with lib.callbacks and how could I prevent this from happening, so that the other users could trust the information they get.