Below is a draft for a blog post explaining what this file is and how to use it.
The file is the third part of a multi-volume split archive created with 7-Zip . This naming convention indicates a large original file was broken into smaller pieces for easier sharing or storage. 5EK18EZQ6L.7z.003
You cannot open part .003 on its own. To get your data back, you need the complete set. Below is a draft for a blog post
: Ensure you have every numbered file in the sequence (e.g., ...7z.001 , ...7z.002 , ...7z.003 ). 5EK18EZQ6L.7z.003