@Musashi Thank you for delivering the promised changes to keyword handling
which yields
<dc:subject>
<rdf:Bag>
<rdf:li>b</rdf:li>
<rdf:li>a</rdf:li>
<rdf:li>m</rdf:li>
<rdf:li>x</rdf:li>
<rdf:li>y</rdf:li>
<rdf:li>z</rdf:li>
</rdf:Bag>
</dc:subject>
<photoshop:SidecarForExtension>RW2</photoshop:SidecarForExtension>
<tiff:Orientation>1</tiff:Orientation>
<exif:DateTimeOriginal>2022-10-22T16:06:32.953+00:00</exif:DateTimeOriginal>
<lr:hierarchicalSubject>
<rdf:Bag>
<rdf:li>b|a</rdf:li>
<rdf:li>b|a|m</rdf:li>
<rdf:li>b|a|m|b</rdf:li>
<rdf:li>x</rdf:li>
<rdf:li>y</rdf:li>
<rdf:li>z</rdf:li>
</rdf:Bag>
</lr:hierarchicalSubject>
for keywords x, y, z, a|m|b (or a>m>b).
Not as good as my proposal at Win 10 PL5.3.1 - Use Keyword Format Templates instead of just reverting to the pre-PL5.2.0 keyword format and Keyword Format Templates - A more flexible way of working with keywords in DxPL but better than what was previously on offer with PL5.2.0 onwards!