whodinner/hex-witch ? reverse-engineered prompt

Build me a simple Python desktop app for security research that helps inspect DMG files without actually mounting or running anything risky.

I want a clean GUI where I can choose a DMG file, see basic file info, and explore what is inside it in a safe read only way. It should feel like an experimental reverse engineering tool, so focus on visibility and analysis, not extraction or modification. If useful, show metadata, headers, file structure, hashes, and any obvious indicators that help someone understand what the image contains.

Please make it easy to run with PyQt5, keep the code straightforward, and include a basic interface that is usable right away. If you need to check current Python or DMG parsing details online, go ahead and look them up. Add sensible error handling and keep the app lightweight since this is meant to be an open source security tool.