What is the components-v2 meaning

recently, i need to develop component secondary,i found components-v2 is a confused conception。when component is v2 ,it very different from normal component. i found this comment in code. but i don’t understand. please tell me the ‘components-v2’ design purpose。

(defn migrate-to-components-v2
“If there is any component in the file library, add a new ‘Library backup’, generate
main instances for all components there and remove shapes from library components.
Mark the file with the :components-v2 option.”