What does ".15g" do with format(float...?

Question

Python

This is a calculator. Line 3 allows you to display only the entered numbers, without zeros and commas.

what does ".15g" do anyway? Are there analogues?

def displayNumber(self,value):

        text = self.sender()

        newLabel = format(float(self.ui.label.text() + text.text()),".15g")
        self.ui.label.setText(newLabel)

Answer 1

Here is the definition

Answer 2

https://pyformat.info/