WikiTree is a single shared tree, like FamilySearch, so the export is a branch around one person rather than "your tree". It does have a proper GEDCOM export.
Where it is
From your profile page, open the family tree and tools menu and look for the GEDCOM export option. Choose a starting profile, whether to include ancestors, descendants or both, and how many generations. The site builds the file and offers a download.
What is in the file
People, relationships, dates and places for the profiles you have permission to see. WikiTree's biographies come along as notes.
What is unusual about it
Sources. WikiTree's practice is to write sources into the biography text, as citations in prose and footnotes, rather than as structured source records. So the GEDCOM has very few SOUR records even for well-sourced profiles. On GED-VIEW's Sources page the list may look nearly empty. The evidence is there; it is in the notes. GED-VIEW shows a panel of notes that appear to contain citations for exactly this case.
Living people. WikiTree's privacy levels control what you can see, and the export respects them. Living profiles you do not manage come through with limited detail or not at all.
Next
Export a few generations around yourself, open the file in GED-VIEW, and read the notes on any well-sourced ancestor.