The Organic Maps project uses Github Discussions to define its roadmap. ROADMAP.md files are common in open source projects but we find they quickly become out of date. We opt for an issues and milestone approach that our maintainers and community can keep up-to-date as work is added and completed.
Milestones define when an issue, pull request, and/or roadmap item is to be completed. Issues are the what, milestones are the when. Development is complex therefore roadmap items can move between milestones depending on the remaining development and testing required to release a change. View active milestones.