-= Validate =-
  wget https://docbook.org/xml/5.0/rng/dbits.rng
  xmllint --noout --relaxng dbits.rng help/C/index.docbook
  jing dbits.rng help/C/index.docbook

-= View the manual using yelp =-
  yelp file:///path_to_file/index.docbook

-= Tests: Generate pdf and html files from docbook =-

  Method I: Use yelp-build (HTML chunk)
    cd help/C
    mkdir htmlout
    yelp-build html -o htmlout index.docbook

  Method II-a: Use docbook5-style-xsl package on Fedora 29 (PDF)
    sudo dnf install -y docbook5-style-xsl
    cd help/C
    xsltproc /usr/share/sgml/docbook/xsl-ns-stylesheets-1.79.2/fo/docbook.xsl index.docbook > eom.fo
    fop -fo eom.fo -pdf eom.pdf

  Method II-b: Use docbook5-style-xsl package on Fedora 29 (HTML)
    sudo dnf install -y docbook5-style-xsl
    cd help/C
    xsltproc /usr/share/sgml/docbook/xsl-ns-stylesheets-1.79.2/html/docbook.xsl index.docbook > index.html

  Method II-c: Use docbook5-style-xsl package on Fedora 29 (HTML chunk)
    sudo dnf install -y docbook5-style-xsl
    cd help/C
    xsltproc --xinclude \
        --stringparam base.dir htmlout/ \
        --stringparam use.id.as.filename 1 \
        --stringparam chunker.output.encoding UTF-8 \
        /usr/share/sgml/docbook/xsl-ns-stylesheets-1.79.2/html/chunk.xsl index.docbook
or
    xsltproc --xinclude \
        --stringparam base.dir htmlout/ \
        --stringparam use.id.as.filename 1 \
        --stringparam chunker.output.encoding UTF-8 \
        --stringparam chunk.section.depth 2 \
        --stringparam chunk.first.sections 1 \
        /usr/share/sgml/docbook/xsl-ns-stylesheets-1.79.2/html/chunk.xsl index.docbook
    cp -rp figures htmlout

  Method III-a: Use docbook-xslt2-2.3.10-app (XHTML)
    cd help/C
    wget https://github.com/docbook/xslt20-stylesheets/releases/download/2.3.10/docbook-xslt2-2.3.10-app.zip
    unzip docbook-xslt2-2.3.10-app.zip
    java -jar docbook-xslt2-2.3.10-app/docbook-xslt2-2.3.10.jar -f xhtml index.docbook > index.html

To upgrade the manual:
sudo dnf install -y docbook5-schemas
xsltproc --output index-new.docbook /usr/share/xml/docbook5/stylesheet/upgrade/db4-upgrade.xsl index.docbook
xsltproc --output legal-new.xml /usr/share/xml/docbook5/stylesheet/upgrade/db4-upgrade.xsl legal.xml

To validate the manual:
xmllint --noout --relaxng /usr/share/xml/docbook5/schema/rng/5.0/docbook.rng help/C/index.docbook
jing /usr/share/xml/docbook5/schema/rng/5.0/docbook.rng help/C/index.docbook
yelp-check validate help/C/index.docbook

To view the manual:
yelp file:///full_path/index.docbook

Note: docbook5-schemas should be installed in your system in order to view the manual (DEPENDENCY)

There is no File menu item in toolbar, it's Image, and edit
actions can be found under Edit menu item instead of Image menu
item.

Fix Open Image dialog title.