Given that, the following long-form article is structured for . It explains what this file might be, the risks involved, and how to safely handle unknown APKs.
The filename Download- com.lustfield-0.3-release.apk -401.86... contains every hallmark of a suspicious, potentially malicious APK: Download- com.lustfield-0.3-release.apk -401.86...
The lack of verifiable information + large size + absence from Play Store = high risk. Given that, the following long-form article is structured