I think that capability of including comments is essential!
For example:
<COMMENT>CRC error on disk. Not yet determined whether it is
a read error, or a deliberate component of copy protection
</COMMENT>
or
<COMMENT>Note that HEAD NUMBER field in sector header is wrong.
Machine uses WD controller, and doesn't care about that field,
therefore, the incorrect value does not need to be replicated
for normal use. </COMMENT>