How to patch XML-files

Gentoo Mono Handbook
https://en.wikipedia.org/wiki/XSLT, http://www.mono-project.com/docs/tools libraries/libraries/xml/, XSLT in Mono: the story of a young hacker,
https://visualstudio.uservoice.com/forums/121579-visual-studio-2015/suggestions/4450357-implement-xslt-3-0-for-net
XSLT to remove "<b>"nodes from here:

<?xml version="1.0" encoding="UTF-8"?>
  <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

  <!--Identity transform copies all items by default -->
  <xsl:template match="@* | node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

  <!--Empty template to match on b elements and prevent it from being copied to output -->
  <xsl:template match="b"/>

</xsl:stylesheet>

http://stackoverflow.com/questions/18352193/xsltemplate-in-mono

xslt processors

msbuild

XmlPeek Task
Returns values as specified by XPath query from an XML file.

XmlPoke Task
Sets values as specified by an XPath query into an XML file.

XslTransformation Task
Transforms an XML input by using an Extensible Stylesheet Language Transformation (XSLT) or compiled XSLT and outputs to an output device or a file.

mono-xmltool

http://linux.die.net/man/1/mono-xmltool
mono-xmltool

Usage: mono-xmltool [options]

options:

	--validate [*.rng | *.rnc | *.nvdl | *.xsd] [instances]
	--validate-rng relax-ng-grammar-xml [instances]
	--validate-rnc relax-ng-compact-grammar-file [instances]
	--validate-nvdl nvdl-script-xml [instances]
	--validate-xsd xml-schema [instances]
	--validate-xsd2 xml-schema [instances] (in .NET 2.0 validator)
	--validate-dtd instances
	--transform stylesheet instance-xml [output-xml]
	--prettyprint [source] [result]

environment variable that affects behavior:

	MONO_XMLTOOL_ERROR_DETAILS = yes : to get exception details.
http://www.mono-project.com/docs/tools libraries/libraries/xml/

For running an xsl[t] transformation over xml, you should be able to use either System.Xml.Xsl.XslTransform or System.Xml.Xsl.XslCompiledTransform from System.Xml.dll.

If you want to use XSLT/XPath 2.0 with .NET you could use Saxon.NET - http://sourceforge.net/projects/saxondotnet/ (this is just the Java version of Saxon running inside IKVM)
https://github.com/Softwariness/XSLT
https://github.com/lendres/XSLT-Processor
msbuild tasks:
https://github.com/alphacloud/MSBuild.Xslt - msbuild task for SAXON xslt processor (Java, MPL, Michael Kay - saxon.sourceforge.net)

2004-05-13, DareObasanjo, Why You Won't See XSLT 2.0 or XPath 2.0 in the Next Version of the .NET Framework
2007-01-29, XmlTeam, will be putting out Community Technology Previews (CTP) with the XSLT 2 functionality and appropriate tooling as the implementation matures
http://stackoverflow.com/questions/831300/what-is-the-current-state-of-xslt-2-0-availability-within-net