Sample LD to load a custom ruleset without modifying Apple's standard PF config

myorg.pf.plist

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE plist PUBLIC "-//Apple Computer/DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>myorg.pf.plist</string>
    <key>Program</key>
    <string>/usr/local/bin/pfstart.sh</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/pfstart.sh</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>StandardErrorPath</key>
    <string>/var/log/pf.log</string>
    <key>StandardOutPath</key>
    <string>/var/log/pf.log</string>
</dict>
</plist>