If the notification persists and you're unsure about its origin or purpose, consider reaching out to the support team of the software you suspect is loading the Opennet plugin.
typically refers to components related to OpenNet (RO) , a Romanian telecom/internet provider, or possibly a generic open-source networking plugin. A “plugin” loaded into an unknown process means: Opennet Plugin Loaded Into An Unknown Process
For certain games, like Black Ops II , Steam's overlay or background processes can interfere with how Nucleus Co-op identifies the game window. If the notification persists and you're unsure about