What is the default bin width for Branch of tree

Dear Root Users,developer,and friends:
I have a question we have filled different variables in tree, When we use “TBrowser” view the distribution of one variable ,What is the default bin width for this Branch of tree?How is the default bin width set?

When plotting histogram from a TTree the bin width is automatically computed from the range of the variables and using a default value of 100 bins. You can however, create first an empty histogram with bin width and range as you want and then later fill it, for example with TTree::Draw