## Description
This commit includes improvements and optimizations to the script:
- Clarified the purpose of the quiet flag with a comment.
- Adjusted conditions for appending to PYTHONPATH and MANPATH variables.
- Enhanced Python executable check for reliability and cross-platform support.
- Improved comments and function clarity.
- Ensured consistency with the original code.
These changes enhance readability, efficiency, and maintainability of the script.
