• I have checked that the issue still exists on the latest versions of the docs on master here

Location of the documentation

https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.fillna.html

Documentation problem

Typo in one of the examples for fillna(). Specifically, the last example with df2 = pd.DataFrame(np.zeros((4, 4)), columns=list("ABCE")) where the last column should be E but is instead D in the printout.

Suggested fix for documentation

Either fix to df2 = pd.DataFrame(np.zeros((4, 4)), columns=list("ABCD")) or fix the printout.