To export many files quickly when migrating from Spine 3.x to 4.x, you can use Spine's command line interface (CLI) to automate the export process. This allows you to run Spine from the command line and export multiple projects in one go. You can find more information about the CLI and how to use it for exporting on the Spine Command Line Interface page. Additionally, there are example scripts available, such as export.sh, which you can adapt to your needs to automate the export of your Spine projects and create texture atlases.
