Comments are a way to make RPM ignore a line in the spec file. To create a comment, enter an octothorp (#) at the start of the line. Any text following the comment character will be ignored by RPM:
# This is the spec file for playmidi 2.3...
Comments can be placed in any section of the spec file. Note that macros are expanded everywhere, so that with multiline macros which would only have the first line commented also escape the percent (%) character: