PyCharm adds current file and parent directory to path

I'm using PyCharm on Windows 10 with Python 3.8. I was trying to get Python imports working from a parent directory using:

import sys
sys.path.append("..")  # Adds higher directory to python modules path.
from trace_recursion import trace

It worked fine, but then I noticed that commenting out sys.path.append("..") # Adds higher directory to python modules path. also worked.

I checked this out running from a terminal, and commenting out sys.path.append("..") broke the program, as expected.

I then did a text comparison of the output of print(sys.path) and the output from PyCharm includes the current file and the project directory, whereas the output when run from a terminal does not.

What is going on here please? Has PyCharm cached the extended path from the first time I ran sys.path.append(".."), or is it some kind of default behavior of PyCharm to add that anyway? Or something else?

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