Is there a reason that GlyphData.xml suggests U+06E6 is a Nonspacing Mark:
glyph unicode=“06E6” name=“yehbelow-ar” sortName=“ar1317” category=“Mark” subCategory=“Nonspacing” script=“arabic” production=“uni06E6” description=“ARABIC SMALL YEH” anchors=“_bottom, bottom”
when, in terms of the Unicode specification, this character is category Lm (Letter Modifier) ?