If I open the package contents and add stuff inside the /Resources directory, the application seems to still be working (with those minor changes it would even still just open Pharo and not my app).
BUT if I upload it to my Google Drive, and then download it, it no longer works, stating that it's broken and must be moved to the trash.
If instead of adding stuff inside I just rename it and change its icon, I can upload and download it and it opens Pharo normally.
So I'm guessing, since the _CodeSignature directory was not present in older Pharo Mac VMs, that someone knows how to work with those signatures, and that it must be the key that's missing to make it work.
Can anyone point me in the right direction? Any tutorial, mail discussion, or whatever that might tell me how they made it work for Pharo might help me make the changes I need to the .app and get my product working.