から:help 'verbose'
:
'verbose' 'vbs' number (default 0)
global
{not in Vi, although some versions have a boolean
verbose option}
When bigger than zero, Vim will give messages about what it is doing.
Currently, these messages are given:
>= 1 When the viminfo file is read or written.
>= 2 When a file is ":source"'ed.
>= 5 Every searched tags file and include file.
>= 8 Files for which a group of autocommands is executed.
>= 9 Every executed autocommand.
>= 12 Every executed function.
>= 13 When an exception is thrown, caught, finished, or discarded.
>= 14 Anything pending in a ":finally" clause.
>= 15 Every executed Ex command (truncated at 200 characters).
This option can also be set with the "-V" argument. See |-V|.
This option is also set by the |:verbose| command.