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<title>Line break suppression on whitespaces wrapped but not contained in ruby boxes</title>
<link rel="author" title="Xidorn Quan" href="https://www.upsuper.org">
<link rel="author" title="Mozilla" href="https://www.mozilla.org">
<span style="white-space: pre"><rb>a</rb><rb>
</rb><rb>b</rb></span>