Roadmap exists in a form of a github project board and is located here.
The roadmap provides a list of features we decided to prioritize in project development. It should serve as a reference point to understand projects' goals.
We do prioritize them based on the feedback from the community, our own vision and other conditions and circumstances.
The roadmap sets the general way of development. The roadmap is mostly about long-term features. All the features could be re-prioritized, rescheduled or canceled.
If there's no feature X, that doesn't mean we're not going to implement it. Feel free to raise the issue for the consideration.
If a feature you want to see live is not present on roadmap, but there's an issue for the feature, feel free to vote for it using reactions in the issue.
Since the roadmap consists mostly of big long-term features, implementing them might be not easy for a beginner outside collaborator.
A good starting point is checking the CONTRIBUTING.md document.