$ whois xslt

XSLT

first released in 1999 · by James Clark

$ guessprog --inspect xslt

year: 1999
paradigm: declarative
family: other
memory: automatic gc
binding: dynamic
safety: strong

XSLT(7)

AUTHORS: James Clark
HISTORY: XSLT, Extensible Stylesheet Language Transformations, was developed at the W3C as part of the XSL effort to style and transform XML documents, with James Clark as editor of XSLT 1.0, published in 1999. Rather than a general-purpose language, it is a declarative, rule-based one: templates match parts of an input tree and describe the output to produce. Curiously, XSLT programs are themselves XML documents. Later versions, 2.0 and 3.0, were edited by Michael Kay, the author of the Saxon processor.
USAGE: A niche but still used language, mainly in publishing pipelines (DocBook, DITA), government and legal document processing, and enterprise integration. Browsers have long supported XSLT 1.0, but browser vendors have announced plans to remove it.
SEE ALSO: XSLT on Wikipedia ↗

$ cat library.xsl

<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="/library">
    <ul>
      <xsl:apply-templates select="book">
        <xsl:sort select="@year" data-type="number"/>
      </xsl:apply-templates>
    </ul>
  </xsl:template>
  <xsl:template match="book">
    <li><xsl:value-of select="concat(title, ' (', @year, ')')"/></li>
  </xsl:template>
</xsl:stylesheet>