The section titled "WHEN & WHERE THESE TERMS APPLY" includes:
> Conversations you have with Copilot through other Microsoft apps and websites
- Conversations you have with Copilot through third-party apps and platforms
- Other Copilot-branded apps and services that link to these Terms
That first point (#4 in the original list) can cover all software, Copilot-branded or otherwise, which, even internally, uses Copilot (perhaps without your knowing so).
Github Copilot (to take your specific example) is both "other Microsoft apps and websites" and "Copilot-branded". So, yeah, those ToS undoubtedly apply to Github Copilot.