1. DomName('WebGL2RenderingContext.isFramebuffer')
  2. DocsEditable()
  3. Experimental()
bool isFramebuffer(Framebuffer framebuffer)

Source 

@DomName('WebGL2RenderingContext.isFramebuffer')
@DocsEditable()
@Experimental() // untriaged
bool isFramebuffer(Framebuffer framebuffer) => _blink.BlinkWebGL2RenderingContext.instance.isFramebuffer_Callback_1_(this, framebuffer);