The platform primarily known for hosting open-source projects is GitHub. It serves as a collaborative platform allowing developers to store, review, and manage code in a version-controlled environment. GitHub’s user-friendly interface facilitates contributions from the global open-source community, making it easier to maintain projects and track changes. Features like pull requests, issues, and wikis enhance collaboration and documentation. Furthermore, GitHub fosters community engagement through discussions and collaboration, making it the go-to platform for developers looking to contribute to or host open-source initiatives.