The files don't have to be in YAML format, as it will also work with files containing plain ol' perl data structures. If both are available, it prefers the YAML version if a YAML-ish module is available with which to parse it. eg, on my CPAN-testing smokers I have ...

$ cat IPC-Run.yml 
---
comment: "Ignore (ADAMK|TODDR)/IPC-Run-0* on netbsd/alpha, cos it brea
+ks"
match:
  distribution: "(ADAMK|TODDR)/IPC-Run-0"
  perlconfig:
    archname: "alpha-netbsd"
disabled: 1

$ cat IPC-Run.yml.dd 
$VAR1 = {
  'disabled' => '1',
  'comment' => 'Ignore (ADAMK|TODDR)/IPC-Run-0* on netbsd/alpha, cos i
+t breaks',
  'match' ...
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The .dd file is auto-generated from the .yml file by this script:

#!/bin/sh

for i in *yml; do
    if [[ ! -s $i.dd || $i -nt $i.dd ]]; then
      echo Rebuilding $i
      perl -MYAML=LoadFile -MData::Dumper -e "print Dumper(LoadFile('$
+i'))">$i.dd
    fi
done
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The file extensions .yml and .dd are significant.