\RequirePackage{pdfmanagement-testphase}
\DeclareDocumentMetadata{uncompress,testphase=tagpdf,activate=tagging,pdfversion=2.0}
\documentclass{article}
\usepackage{xecjk}
\usepackage{ruby}
\ExplSyntaxOn
\cs_set_eq:NN\tagmcendpush\tag_mc_end_push:
\cs_set_eq:NN\tagmcbeginpop\tag_mc_begin_pop:n{}
\ExplSyntaxOff
\NewCommandCopy\ORIruby\ruby
\DeclareRobustCommand{\ruby}[2]{%
\leavevmode\tagmcendpush
\tagstructbegin{tag=Ruby}%
\ORIruby
{\tagstructbegin{tag=RB}\tagmcbegin{tag=RB}#1\tagmcend\tagstructend}