OwnCloud was installed via cPanel on the server using the softaculous service.
Before installation, you need to activate the modules in the PHP settings:
Even if you install OwnCloud manually, after installation and the start of the main page, a message appears that you need to activate the corresponding modules (indicated above).
OwnCloud has own Market of add-ons. You can install additional improvements in it, such as playing media files, integration with calendars, and more.
But when trying to install the necessary add-on, an error appeared:
Archives of type application/octet-stream are not supported
in the Russian version:
Архивы application/octet-stream не поддерживаются
The solution is very simple, just activate PHP module: fileinfo
After activation, all add-ons are installed perfectly.
I hope the information was useful!