It's even worse it seems:
"As opposed to code generators trained using copyrighted code (GitHub Copilot, among others), StarCoder 2 was trained only on data under license from the Software Heritage, the nonprofit organization providing archival services for code."
Software Heritage archives FOSS code, which is copyrighted and may even contain GPL code.
In which case all code generated by StarCoder 2 is automatically licensed under the GPL.