I use playwright python in silent mode, my app runs in a background with no windows.
The Windows platform has a special way to run such applications - pythonw.exe
When I start the browser from my code, an unwanted black console window appears on the screen.
How to reproduce the problem:
Let's take simple script like this:

from playwright.sync_api import sync_playwright
with sync_playwright() as p:
    browser = p.chromium.launch()
    page = browser.new_page()
    page.goto("http://playwright.dev")
    page.screenshot(path="example.png")
    print(page.title())
    browser.close()

If we run this script like this:
python.exe sample.py
Everything will work fine and no windows will appear
If we run it like this
pythonw.exe sample.py
We will see a black console window associated with the call to playwright.cmd in the playwright-python library code.
At start pythonw.exe the console is not created, and sys.stdout is set to None.
Therefore, the playwright.cmd subprocess cannot join to the current sys.stdout (because it is None) and creates a new one