Where can I find info about the syntax of column.status?

From the Git documentation about the git status command:

--column[=< options>]
--no-column
Display untracked files in columns. See configuration variable column.status for option syntax. --column and --no-column without options are equivalent to always and never respectively.

I can't see the option's syntax, because the git config column.status returns nothing. Where can I find info about this syntax? The git help status command shows the same info.

Look into the man page of git-config, either git config --help or man git-config should give you man page. This option says to look into column.ui description, which I show here for you:

column.ui
   Specify whether supported commands should output in columns. 
   This variable consists of a list of tokens separated by spaces or commas:

   These options control when the feature should be enabled (defaults to never):

   always
       always show in columns

   never
       never show in columns

   auto
       show in columns if the output is to the terminal

   These options control layout (defaults to column). Setting any of these implies always if none of always, never, or auto are specified.

   column
       fill columns before rows

   row
       fill rows before columns

   plain
       show in one column

   Finally, these options can be combined with a layout option (defaults to nodense):

   dense
       make unequal size columns to utilize more space

   nodense
       make equal size columns