bug#79261: coreutils 9.7 "date -u" - timezone offset is in the wrong direction

On 2025-08-25 14:15, James Feeney via GNU coreutils Bug Reports wrote:
> For anyone inclined to accept my appeal to ISO 8601, the current display format returned by `date -u`, especially within the USA, is wrong, and that is a bug that needs to be fixed.
> 
> Are you inclined to accept the time format of ISO 8601 for the display of UTC - or no?

We should not change the behavior of plain 'date -u' based on any 
arguments presented so far in this thread. The current behavior is 
longstanding, documented, required by POSIX, and plenty of people 
undoubtedly depend on it.

To get 24-hour notation for UTC with 'date', you can run this:

   date -u +'%Y-%m-%d %H:%M:%S'

or this:

   LC_ALL=C date -u

Either of these work with any POSIX-conforming 'date'. GNU 'date' has 
other options (--iso-8601, --rfc-3339) that may be more convenient but 
are less portable. This sort of thing should be enough to satisfy the 
need here.