Motion-5.5.3.dmg Here

: Share your finished animations as high-quality video files or image sequences. Apple Support Important Note: Ensure you are using a legitimate copy from the Mac App Store

Improved performance and reliability when playing back or HEVC media. Motion-5.5.3.dmg

Released as a maintenance update, version 5.5.3 focused primarily on performance stability rather than new creative tools. Motion release notes - Apple Support : Share your finished animations as high-quality video