Use a tool like VirusTotal to upload the .7z file and check for malicious scripts.
A very small file (KB) usually indicates a script or text data, while a large file (MB/GB) suggests media or executable software.
Before opening or "reviewing" the performance of the files inside, ensure you:
Knowing the context (e.g., a specific game mod or a phone utility) would allow me to give you a much more detailed breakdown.