A neat subgenre of quines: invalid programs that print their own source code!
$ python https://reproducing.py/
File "https://t.co/z9z9h8CFOT"" target="_blank" rel="noopener noreferrer">https://t.co/z9z9h8CFOT";, line 1
File "https://t.co/z9z9h8CFOT", line 1
^
IndentationError: unexpected indent