ROOT File: How does it look like? Beginner's Question

I have a very beginner’s question. I am reading about ROOT files, and I do not quite understand it. What does a ROOT file look like?

Thank you!!

ROOT Version: Not Provided
Platform: Not Provided
Compiler: Not Provided


TFile

ROOT Primer -> File I/O and Parallel Analysis -> Storing ROOT Objects

ROOT User’s Guide -> Input/Output

ROOT How To -> Input/Output

For any struggling with the same issue. Writing:
root [0] TFile file = new TFile(“afile.root”)
(TFile ) 0x7fffdf156300
root[1] file->ls()
TFile
muons.root
TFile* muons.root
KEY: TH1F mass;1 masses
KEY: TNtuple tnt;1 tnt
root [1] tnt->Scan()

lets you see what variables (leaves) are inside your TNtuple created in your root file