Hi Sarah! Thanks for reporting the issue. To start off, I added basic support for frontmatter parsing so that the editor distinguishes MD content from frontmatter. PFA screenshot of the updated parsing logic.

I am planning to add better support for frontmatter tags by integrating it with Article settings (Settings button on the top right of the editor page).

Please let me know if you have any suggestions or feedback on how you would like to interact/view frontmatter tags in the live preview or settings.