Sample com.apple.ManagedClient.preferences .mobileconfig

profile_managedclient_type.xml

<key>PayloadContent</key>
<array>
    <dict>
        <key>PayloadContent</key>
        <dict>
            <key>com.apple.SoftwareUpdate</key>
            <dict>
                <key>Forced</key>
                <array>
                    <dict>
                        <key>mcx_preference_settings</key>
                        <dict>
                            <key>CatalogURL</key>
                            <string>http://sus.my.org/index.sucatalog</string>
                        </dict>
                    </dict>
                </array>
            </dict>
        </dict>
        <key>PayloadDisplayName</key>
        <string>Custom: com.apple.SoftwareUpdate</string>
        <key>PayloadEnabled</key>
        <true/>
        <key>PayloadIdentifier</key>
        <string>com.apple.mdm.test-vm-ml.cdaad.concordia.ca.53ae9330-a48d-0130-fde4-000c29505c8e.alacarte.customsettings.6a5f1ba0-a48d-0130-fde6-000c29505c8e</string>
        <key>PayloadType</key>
        <string>com.apple.ManagedClient.preferences</string>
        <key>PayloadUUID</key>
        <string>6a5f1ba0-a48d-0130-fde6-000c29505c8e</string>
        <key>PayloadVersion</key>
        <integer>1</integer>
    </dict>
</array>

@timsutton this says 10 years ago - is this still the right format - could i

1. change "com.apple.SoftwareUpdate" to com.myorg.whatever
2. CatalogURL to myCustomKey and http://sus.my.org/index.sucatalog to myCustomValue
3. and read with nsuserdefaults?

of course, you can say i have no idea or i dont support a random 10 year old gist or ignore :)
[Edit] Ok, so poking around i see this tool you made was very popular, nice job.