The app Markdown Tables does not collect or use any personal or private information on your device.
You paste Markdown text into the app which is stored in memory. The app does keep a single copy of the last table being edited locally on your device so that you can continue editing the table if the app is restarted.
This app does not make use of any third party crash reporting or analytics frameworks. The only analytics collected are those shared by Apple - these can be opted out of by going to Settings > Privacy > Analytics > Share With App Developers.