Detecting Openplanet in ManiaScript
To detect Openplanet in ManiaScript, you check the value
SystemSkuIdentifier on the clientside. If this value is equal to
ESystemSkuIdentifier::EU, it means Openplanet is installed and running.
Note that this works only on the side where Openplanet is running, so if you want to check on the server if some client is running Openplanet, you'll have to send them a Manialink with the detection code and do a netwrite request and netread response.