This looks like a Base64 or randomly hashed string. It is often used to: Bypass automated copyright filters. Prevent search engines from indexing the contents.
This is a 7-Zip compressed archive . It is known for high compression ratios and is safe as a format, though the contents depend entirely on the source. File: NNBklMGB2K16.7z ...
However, based on the naming convention and extension, here is a general assessment: File Characteristics This looks like a Base64 or randomly hashed string
If it’s very small (KBs), it might be a link-redirect or malware. If it's large (GBs), it’s likely media or a software package. To help me give you a better "review," could you tell me: Where did you find/download it? (A specific site or forum?) What is the file size? This is a 7-Zip compressed archive
Many .7z files with names like this are password-protected.