For horizontally written text, the text alignment is always visually right-aligned (that is, left-to-right and right-to-left are treated uniformly). For vertical text, this is equivalent to kCMTextMarkupAlignmentType_End.
Mac Catalyst 13.0+Beta
While readers should be prepared to account for kCMTextMarkupAlignmentType_Right being equivalent to kCMTextMarkupAlignmentType_End for vertical text, authors are discouraged from using kCMTextMarkupAlignmentType_Right for vertical text.
This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.