Re: How to format this type of timestamp

[Eli Zaretskii]

> Date: Sat, 3 Oct 2020 14:55:10 +0300
> From: Jean Louis <bugs@gnu.support>
> 
> I would like to format this: (date . "1599712637489") to something
> like 2020-10-02 20:06:41.119184+03
> 
> Here it works, I get: Saturday, March 24, 2018 6:08:38.010 PM
> https://www.epochconverter.com/
> 
> That is probably the right time.
> 
> Which function should I use, I tried format-time-string, but is not
> working.

Where did you get the value 1599712637489?  What is its semantics?
The number of seconds since the epoch is several orders of magnitude
smaller.  E.g., this works:

  (format-time-string "%c" 1599712637.489)

where I divided the value you provided by 1000.