On Wed, Dec 16, 2020 at 01:52:56PM +0100, Emanuel Berg via Users list for the GNU Emacs text editor wrote:
> Aaah, this was nice:
> 
>   (setq echo-keystrokes 0)
> 
> But how can I make Emacs even more silent?
> 
> For example, how can I inhibit/suppress the annoying and (for
> me) meaningless
> 
>   Auto-saving...done
>   Mark set
>   Quit
> 
> ?

At least to one of those I can offer an answer. Quoth the Emacs
manual:

    18.6 Auto-Saving: Protection Against Disasters
    ==============================================
    
    [...]

    When Emacs determines that it is time for auto-saving [...]
    When the ‘auto-save-no-message’ variable is set to ‘nil’
    (the default), the message ‘Auto-saving...’ is displayed
    in the echo area during auto-saving, if any files are actually
    auto-saved; to disable these messages, customize the variable
    to a non-‘nil’ value.  Errors occurring during auto-saving
    are caught so that they do not interfere with the execution of
    commands you have been typing.

So set (or customize) `auto-save-no-message'. Found by searching
for `message' in the Emacs manual.

Cheers
 - t