The standard version of DMG Extractor often comes as a "Home" or free edition with specific limitations:

Accessing encrypted or password-protected DMG files usually requires a paid license.

Premium users can extract large archives (greater than 4GB) without the session limits imposed on free users.

The free version typically restricts users to extracting only a small number of files (often up to five) at a time.

The activation key is a unique alphanumeric code provided upon purchasing a license, typically priced around for full access. Free Alternatives: No Key Required

Another open-source utility that supports DMG extraction alongside hundreds of other formats.