Before opening it, upload the file to VirusTotal . This service runs the file through dozens of antivirus engines to check for hidden threats.
On platforms like Nexus Mods or GameBanana , download files are often renamed to their internal database ID to prevent naming conflicts. 57293.rar
Look at the URL where the file was hosted. For example, if it came from ://example.com , the website's purpose will tell you what is inside. Before opening it, upload the file to VirusTotal
Be wary of files inside named things like document.pdf.exe . This is a common trick to hide an application as a document. Before opening it