This means you have the rights
- to distribute
- to inspect
- to modify
- even to sell
Under a single condition: every recipient of your work must get the same honourable open-source-rights and full access to your modified sources.
GPL v3 FAQ: https://www.gnu.org/licenses/gpl-faq.en.html
Full license text: https://www.gnu.org/licenses/gpl-3.0.en.html
Our binaries: https://github.com/OpenHoldem/openholdembot/releases
Our sources: https://github.com/OpenHoldem/openholdembot