I found that doc by going to Cachex’s dependency hex page (the first page I go to for any library):
Then I clicked the link that stated Online documentation, which took me to:
Which I then switched to night mode because Ow My Eyes… o.O
It shows two modules, they are:
-
Cachex
- Cachex provides a straightforward interface for in-memory key/value storage
-
Cachex.Disk
- This module contains interaction with disk for serializing terms directly to a given file path. This is mainly used for backing up a cache to disk in order to be able to export a cache to another instance. Writes can have a compression attached and will add basic compression by default
I then clicked on the top one as it’s the main interface for it, which took me to:
In the functions section I clicked the get function and it took me to the link I linked. 
‘Almost’ every hex library has their docs on hexdocs at a path of https://hexdocs.pm/<library_name> for note, which is linked from Hex as well (specific versions if you want too).
But yep, it’s linked on the front-most hex page of the library itself.
