When you compile JSX to JavaScript, it produces a series of function calls representing the structure of the JSX. In a recent major version, React added a new set of functions which are more efficient at both runtime and during transport, and don't require an explicit import (which helps cut down on unnecessary dependencies).
It improves the bundle size for most apps because the imported functions can be minified better. Depending on your bundler, it can avoid function calls at runtime.
