It's not a matter of something you can disagree on Kimber. By Definition, a Plugin is a piece of Software code for enhancing a particular program's capabilities. Period. Tubes do NOT fit the definition by any stretch of the imagination. Tubes are content. Not Code.
A plugin (plug-in, addin, add-in, addon or add-on) is a computer program that interacts with a host application (a web browser or an email client, for example) to provide a certain, usually very specific, function "on demand". Applications support plugins for many reasons. Some of the main reasons include: enabling third-party developers to create capabilities to extend an application, reducing the size of an application, and separating source code from the an application because of incompatible software licenses.
For CG related Plugin's, most items are in some form of python script or other scripting language language. As far as PSP goes, Scripts such as the ones found Here could be considered plugins.
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