When setting:
<xsl:param name="activate.external.olinks" select="0" />
And also:
<xsl:attribute-set name="xref.properties">
<xsl:attribute name="color">#47a</xsl:attribute>
</xsl:attribute-set>
The blue (#47a) color disappears in PDF for <olink> elements, but the blue continues to show up for <link xlink:role="http://docbook.org/xlink/role/olink"> elements.
To try it out for yourself, clone https://github.com/markcraig/DOCS-47, build with mvn pre-site. Then consider target/docbkx/pdf/other-book.pdf. (The first link in that book's only chapter is with <link xlink:role="http://docbook.org/xlink/role/olink">, the second is with <olink>.
As discussed on docbook-apps, this is not the intended behavior. Instead, <link> elements with the olink role should behave as <olink> elements
I checked in a fix for this. It should appear in the next snapshot build.
Thanks Bob, I tried the fix in the snapshot, and it definitely makes my color problem go away.
Looking forward to picking this up in the next release.