Many 7z files are encrypted. If the extraction tool asks for a password and you don't have one, it’s likely a protected backup from a service you used previously.
A name like 625eb0826ca18 is typically a or a unique ID . These are often generated by: 625eb0826ca18.7z
To see what's inside, you will need a file archiver that supports the 7z format. Many 7z files are encrypted