summary.txt: summary of results
      log.txt: log of progress
  ignore.html: -----   1 ignored file
 ignoreX.html: -----   1 ignored file (cross referenced)
    warn.html: warn    2 warnings
   warnX.html: warn    2 warnings (cross referenced)
   warnF.html: warn    1 file with warnings
httpfail.html: -----   1 link: failed via http