Files with a extension are compressed archives typically opened with tools like WinRAR or 7-Zip . If you encountered this file in a suspicious context (such as an unsolicited email or an untrusted download site), it is highly recommended to scan it for viruses using a service like VirusTotal before attempting to open it.
No specific public records or widespread social media posts were found concerning a file named "Sobrina.rar."
If "Sobrina" refers to a specific person or a niche internal project, it likely belongs to a private network or specific community that hasn't gained broader online visibility.
Could you provide more context, such as or what the file is supposed to contain?