Export before anything irreversible
Cleaning up orphaned languages, deleting a series of events, handing the group to someone else - all of them are easier to be relaxed about with a fresh archive on disk. It costs one click.
The export is a ZIP of your group's data, downloadable at any time, importable into a self-hosted MeetAgain. It exists so that staying is a choice rather than a consequence.
Export in the group settings is a single button and a list of what comes out. There is nothing to configure and no waiting - it builds the archive and hands it to you. It is worth taking one occasionally even if you have no intention of leaving; a copy of your own content is a reasonable thing to have.
Press Download Export
The ZIP is built and downloaded. Nothing changes in the group and nobody is notified.
Keep it somewhere real
A copy on your own machine or in your own storage. An export sitting in a downloads folder is not a backup.
Import it if you ever move
A self-hosted MeetAgain takes the archive under Admin, System, Import. The core is open source, so a self-hosted instance is a real option rather than a theoretical one.