Otherwise not last

xsl:otherwise is the default branch of an xsl:choose, chosen only when no xsl:when matches, so it belongs last. Anything after it — another xsl:when, a second xsl:otherwise — is invalid: a processor rejects the misplaced xsl:otherwise, and a reader is misled into thinking a later branch can run.

The check is report-only: reordering the branches so xsl:otherwise comes last is a structural move that waits on the full-fidelity parser (#228).

Incorrect:

<xsl:choose>
  <xsl:otherwise>none</xsl:otherwise>
  <xsl:when test="@a">a</xsl:when>
</xsl:choose>

Correct:

<xsl:choose>
  <xsl:when test="@a">a</xsl:when>
  <xsl:otherwise>none</xsl:otherwise>
</xsl:choose>