<convex_mesh> Child Elements section starts with "No child elements are required" but then gives min occurrences of 1 for <source> and <vertices>. The 1 isn't correct.
a) Change <source> to 0 or more, <vertices> to 0 or 1.
b) Move related comments "Required if convex_hull_of is not specified" in parens into the occurrences column.
c) Then "No child elements are required" isn't required; remove & rephrase intro sentence.