Export functionality is available in Jira Administration -> Add-ons section
Using this tool, you are able to make a backup of all the scheduled issues in the system along with the configuration of the add-on. It is recommended to export your Scheduled Issues before making a major version upgrade (such as The Scheduler 4.x to The Scheduler 5.x) as an additional security measure.
You can export Scheduled Issues from all projects at once or export only selected projects. Additionally, you can skip exorting inactive or invalid Scheduled Issues.
After clicking on "Export" button at the bottom of the page, The Scheduler will generate an .xml file for you to download.