To access the contents of this file, you cannot simply open the .001 file alone. You must follow these steps:

: Always run the file through a service like VirusTotal or scan it with updated antivirus software before opening the contents.

: You must have every numbered segment in the same folder (e.g., PrettyButterflies.7z.001 , PrettyButterflies.7z.002 , PrettyButterflies.7z.003 , etc.).

Do you have the of this archive, or are you trying to verify the source where you found it?

: The underlying compression format is 7-Zip, which uses the LZMA algorithm for high-ratio data compression.