How to reproduce:
1. Open Unity Hub
2. Download an Editor with the Documentation module
3. Open the terminal
4. Navigate to the "Manual" directory ("/Editor/Data/Documentation/Documentation/en/Manual") using the "cd" command
5. Execute the "ls -l" command

Expected result: all the HTML files have read permission for all users and write permission for the owner
Actual result: all the HTML files are missing all of the permissions and therefore are unopenable

Reproducible with: Hub 2.4.2 (2018.4.29f1, 2019.4.15f1, 2020.1.13f1, 2020.2.0b12)
Could not test with: Hub 2.4.2 (2020.1.0a6) documentation isn't available yet

Notes:
-Tested on Ubuntu 18.04 VM
-Permissions can also be checked with the "stat" command in the terminal
-Using the "chmod" command to set read permission for all users makes the files readable
-All of the files (HTML, CSS, JS, and all of the images) except folders seem to be affected