The author is a value which can be set by the content-manager. By default set the creator as the author on creation time and the content-manager can select another contact in the settings-tab. Therefor the author is a prefilled mandatory value.
This behavior can be influenced by the configuration and make the author an optional nullable value.
sulu_article:
default_author: false
When this configuration isset the author will no be prefilled and can be set optional in the settings-tab. If is was not
set the author
variable in twig will stay null
.