CDATA case-insensitivity question

cmark's inline raw HTML and HTML block matchers accept the literal `<![CDATA[` case-insensitively, treating `<![cdata[`, `<![CDATa[`, `<![cDaTa[` etc. as valid CDATA opens. CommonMark 0.31.2 §6.6 specifies the exact string `<![CDATA[` (case-sensitive), and that wording inherits the underlying XML 1.0 (Fifth Edition) production `[19] CDStart ::= '<![CDATA['`, which is case-sensitive (XML is case-sensitive throughout). cmark's matcher has matched case-insensitively since the initial commit, but the commit history doesn't show any deliberation about CDATA specifically; is this leniency intended (in which case the spec needs amending) or incidental (in which case the matcher should tighten)?