In OpKey, Sikuli specific keywords are plug-in specific keywords.  Test scripts created with these keywords can be executed by only using specific plug-ins. For example, Sikuli specific keywords can only be executed by the Sikuli plug-in.

Some Sikuli specific keywords include: Click, DoubleClick, DragDrop, PasteTextOnEditBox, ResetImageScaleFactor, and many other keywords.

For detailed information on Sikuli specific keywords, please refer: Sikuli Specific Keywords