How to embed arbitrary text/data in SVG files?

Question

I have created a diagram with tikz and pdflatex and converted it to SVG with inkscape. I want to embed the latex code into the .svg file so that others are able to regenerate/modify it. The problem is that tikz code contains lots of -- (to draw lines) and this makes it impossible to add the code as is as an XML comment to SVG (see this other question).

I was thinking about adding it as CDATA but failed so far (i.e. http://validator.w3.org/ does not validate it).

Here is a MWE of what Carlo Cannas suggested:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   id="svg2"
   version="1.1">
    <metadata>
        <annotation xmlns="http://www.w3.org/1998/Math/MathML" encoding="TeX">
            blah --
        </annotation>
    </metadata>
</svg>

Answer 1

You may include it in a metadata element, as normal text or using other elements.

I'd suggest to include the code in a MathML annotation element, with the appropriate encoding attribute. MathML namespace URI is http://www.w3.org/1998/Math/MathML, so at the end the code will be something like this:

<svg xmlns="[...SVG namespace URI here...]">
    <metadata>
        <annotation xmlns="http://www.w3.org/1998/Math/MathML" encoding="TeX">
            <!-- TeX code here (obviously not in this comment, remove this whole line and write it in a CDATA section or as character data, as you wish) -->
        </annotation>
    </metadata>
</svg>