Yes if you are the only developper and never received nor accepted external contributions or if you managed to get permission from every single person who contributed or replaced their code with your own.
This makes it sound more difficult than it actually is (logistically); it's not uncommon for major projects to require contributors to sign a CLA before accepting PRs.
"I will not expose people taping out Hazard3 to the possibility of your employer chasing you for your contribution by harassing them legally. A contribution agreement does not solve this, because you may sign it without the legal capability to do so (...)"
https://github.com/Wren6991/Hazard3/blob/stable/Contributing... (this is I believe the repo with design for riscv cores running on RPi Pico 2)