If the plugin itself has no function or meaning standalone, without being linked to the GPL'd work, it's considered by the GPL to be a "derived work". And at l

If the plugin itself has no function or meaning standalone, without being linked to the GPL'd work, it's considered by the GPL to be a "derived work". And at least on GPL v2 that OBS uses, it operates at the point of "distribut[ing] or publish[ing]" that. v2 sect 2b You must cause any work that you distribute or publish, that in whole or in part contains or is derived from the Program or any part thereof, to be licensed as a whole at no charge to all third parties under the terms of this License. https://www.gnu.org/licenses/old-licenses/gpl-2.0.html https://www.gnu.org/licenses/old-licenses/gpl-2.0.html