PostureCorrector od Softmaximalist

✓ Real-time detection of slouching
✓ Receive alerts through desktop notifications
✓ Comprehensive statistics
✓ Track your progress over the most recent 120 days
✓ See how your posture changes based on activity types
✓ Understand your posture patterns throughout the day
✓ Customizable settings to improve efficiency and accuracy
✓ Customize posture detection frequency for your computer
✓ Fine-tune posture detection with two threshold values

The source code is publicly available on GitHub for review. You can find the link to the GitHub page on the official website of PostureCorrector. The website is accessible from the "home" button of the popup page. Additionally, note that the PostureCorrector extension runs entirely on your local machine. Your webcam footage, user statistics, etc are stored on your browser that only you can access. This also means that the extension never communicates with external servers. If you are still in doubt, you can try the extension without internet connection and you would see that the extension still works.