What does "MEIPASS" stand for?

Question

PyInstaller sets the sys._MEIPASS attribute to let the application know where to find its bundled resources. Source: this answer.

I know what _MEIPASS does. What does the name _MEIPASS mean? What does it stand for?

• This was changed from an MEIPASS2 environment variable in version 2.0.
• Nothing in the official documentation even alludes to the etymology of this variable.
• It appears to have been around since the beginning of PyInstaller.

Answer 1

According to Codewarrior0 (AKA: David Vierra) one of the pyinstaller developers:

It comes from PyInstaller's ancestor, McMillan Enterprise Installer. Not sure about the PASS part, though.

(Source)