To see what is inside the file, you need a utility that can decompress RAR files. Common options include:
A popular choice for macOS users to handle various archive formats. Safety and Troubleshooting
It may be a compressed backup of a specific tool or library (e.g., "M" and "G" representing specific project initials). How to Access the Content
Because .rar is a container format, the specific "useful content" inside depends entirely on its source. Generally, files with this naming convention are found in: