The "make docs" target currently uses the <font> tag in this macro:

define GenerateBottom
  <font size="-1">$(if $(strip $3), $(strip $3))<br> $(if \
      $(strip $2),<a href="$(strip $2)">Copyright</a>,Copyright) \
      &copy; $(strip $1), $(COPYRIGHT_YEAR), $(FULL_COMPANY_NAME). \
      $(COMPANY_ADDRESS). All rights reserved.</font>
endef

This one macro is the root cause of the single biggest issue when generating HTML5 docs, since it is injected into every file.

This should be changed to use
    <span style="font-size:smaller"> ... </span>