Why is there a shortage of free space?

[Android Central Question]

I just bought a new huawei nova lite phone with 16 GB internal storage. Available storage is about 9.5 GB which makes sense as 6 GB is probably used to run the firmware.
The problem is only 6.3GB is free from the available 9.5GB. About 1.1GB is taken up by pre-installed apps and media files. Where is the other 2.1GB???

 

[Rukbat]

In hidden files you can't see unless you're rooted.