Please explain why the need for a babel plugin transform runtime?

Found some information in English only, but at the moment it is not strong. I would like to more or less explained in detail why we need this plugin. Thank you.
July 2nd 19 at 13:59
1 answer
July 2nd 19 at 14:01
He looks code for ES6 features and if they are, transformerait code so that these features were taken not from global scope and imported from babel-runtime.

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