>>> "RP" == Robert Pluim <rpluim@gmail.com> writes:

   >>>>>> On Thu, 04 Mar 2021 15:22:21 +0100, Uwe Brauer <oub@mat.ucm.es> said:
   Uwe> Sorry, you misunderstood me, this time string, inserts the time string,
   Uwe> when I execute the capture, but I want to extract the time string, when
   Uwe> the message was received. This is why I used 
   Uwe> %:date
   Uwe> in my first attempt, that works but inserts 
   Uwe> Tue, 2 Mar 2021 19:35:03 +0100  

   Uwe> Which I find way too long.

   Uwe> Just 
   Uwe> Tue, 2 Mar 2021 

   Uwe> Would be fine or 02.03.2021

   Uwe> But not the hour, seconds etc

   > It looks like the %:date handling respects the
   > 'org-time-stamp-formats' variable, so if you can arrange for that to
   > be let-bound appropriately during the capture process, it might do the
   > right thing.

Hm that variable is set to 

Its value is ("<%Y-%m-%d %a>" . "<%Y-%m-%d %a %H:%M>")

So if I call with a prefix it inserts 
<2021-03-04 jue 21:19>

But nothing like +0100  

I am not acquainted with let-bound (only with let)

So are you saying I should may use defadvice to modify org-capture?