Official developers have warned against fake websites (like melonds.org ) that exist to leech traffic and provide potentially unsafe files.
Downloading emulators in .zip files containing "MOD" or "MASTER EDITION" labels from third-party sites carries significant risks: melonDS MOD APK Beta v1.7.0 MASTER EDITION.zip
If you are looking for a high-quality Nintendo DS experience, the official melonDS app is a strong contender: Official developers have warned against fake websites (like