In the PureCN coverage QC file, are the mean duplication columns in FRACTIONS OF READS that are duplicated, or in X (number of reads that are duplicated)?

Also, several of the column names start with "mom".  Does this mean "mean of means"??

It's simply the mean of the duplicated.rate column in the coverage file, so fractions. mom is median divided by mean and is a simple metric of skewness. The QC file is still experimental, likely to change and thus largely undocumented. There should be a warning in the documentation.