Microsoft controls Bitcoin?

Bitcoin's core source code is hosted on GitHub, and it's generally understood that no harmful code will be merged into the main branch unless it's approved by the developers overseeing the project.

Given the vigilant monitoring by numerous developers, any malicious changes are likely to be quickly noticed and addressed.

However, consider a hypothetical scenario where an individual employed by Microsoft, which owns GitHub, decides to clandestinely alter the Bitcoin code stored in its database.

This act could potentially go unnoticed by the repository's maintainers (since it would not be tracked in history).

Consequently, node operators might download and run this altered version, unknowingly executing malicious code.

Is such a scenario feasible?