This indicates the file is compressed using the 7-Zip archiving tool. To find out what is in this file:

Likely an index number, item number, or day (e.g., the 10th item or July 10th).

Once extracted, you will be able to see the files and documents inside.

Use a file archiver tool like 7-Zip (Windows), The Unarchiver (Mac), or a command-line tool to extract the file.

Likely indicates the project or topic (e.g., Screenshot, Sample, Subject, Secret). Jul: Indicates the month of July.

Often indicates a "small" version, "sample", or "short" version.