Can be possible a back up from a stolen Mac?
My MacBook Pro was stolen and is offline according to find my device app.
MacBook Pro 13″, macOS 10.14
Question marked as
Put simply, no, you cannot back it up if it is stolen and definitely not if it is offline. If you were using iCloud Drive or things such as Contacts and iCloud Photos to sync with your mobile devices then any files should still be present in iCloud and accessible by logging into icloud.com with a web browser, or will reappear on a new Mac signed in with the same Apple ID.
Access iCloud Drive files from your iPhone and other devices - Apple Support - https://support.apple.com/HT203052
Add your Desktop and Documents files to iCloud Drivehttps://support.apple.com/HT206985
Related (yes, yes, it says iPhone..., but the key thing is about items that use iCloud as a backup source) : About missing information after you restore your iPhone, iPad, or iPod touch with iCloud Backup - Apple Support
