Currently, all files in doc-files sub-directories are simply copied to the output directory, including HTML files.
It would be better to wrap such pages with a standard header and footer, this also implies that these
files will get the copyright files wrapping if any, and these are specified with -top, -bottom options.
The header/footer described above really translates to -top/-bottom of the javadoc options.

There are several advantages, such as copyright wrapping html validation via doclint, etc.

All other files besides .html/.htm files will be copied to the output as-is.