what is dtype at the last line while checking dtypes for all columns in Python Pandas dataframes

Question

What is the dtype at the last line here in the output, i am confused -

df.dtypes
#A     int64
#B      bool
#C    object
#dtype: object

Here i am only asking about the last line which is 'dtype: object'. I am not asking why it is not str, my question is what is this line for?