The template is in the template.html file. Note that comment markers are used to control how the template.awk Awk script generates the C header which gets ultimately included in the compiled object code. Comment markers have the <!-- var identifier --> format. Here identifier must be a valid C identifier. All the text following the marker until the next marker will be flattened into a C string.
If the identifier is NONE (capitalized) the text from that marker up to the next marker will be discarded.
You will need Awk. I hope any decent implementation will do, but the GNU one is known to work flawlessly. Just do:
$ awk -f template.awk template.html > template.h