Bgsk.7z (Fast)

It is an open-source format, generally managed by the free 7-Zip software. How to Open bgsk.7z :

Based on the file extension , this is a 7-Zip Compressed Archive file. It acts as a container for one or more files and folders, highly compressed to reduce file size. Key Information About 7z Archives: bgsk.7z

Alternatively, if you're comfortable doing so, you can use 7-Zip to extract it and check the files themselves. It is an open-source format, generally managed by

Supports strong AES-256 encryption, allowing for password-protected files. It is an open-source format

Note: Since this is a compressed container, its specific contents ("informative report") are only revealed once it is extracted.