Users are unable to download content in EOS

[kbogert]

After creating accounts for my kids in Endless OS, they were unable to use the bundled Endless Key because every download failed. When clicking on a download link, a yellow caution icon next to a retry icon is displayed, but no other error messages can be found.

I fixed this by running: sudo chmod o+w /var/lib/endless-key/data -R

I'm not able to figure out why this works, all files and directories are owned by kolibri and this is the user Endless Key seems to be running as when they are logged in.