Quoting from the license agreement:
> You may not use the Apple Software, Apple Certificates, or any Services provided hereunder for any purpose not expressly permitted by this Agreement, including any applicable Attachments and Schedules. You agree not to install, use or run the Apple SDKs on any non-Apple-branded computer, and not to install, use or run iOS, iPadOS, macOS, tvOS, visionOS, watchOS, and Provisioning Profiles on or in connection with devices other than Apple-branded products, or to enable others to do so.
Both xtool itself, and anyone who uses it, is violating this license agreement, and apple has shown itself in the past to be a real ass about this sort of thing.
I think this can fly under the radar as long as no one uses it, but as soon as people actually start using this tool in any significant amount, I wouldn't be surprised if apple comes for it.