On a movie or television show what is the job of the gaffer?

Wow, there's much more to this job than I realized.

what an interesting and relevant question and answer.

I always wondered what the Best Boy did. And now, if a woman holds that job is she still credited as Best Boy?

Wonder if any connection to using the term the Gaffer, as the manager of an English football team ?

I was wrong, I guess it’s different from go-for (goffer ) brands runner. ! ! !