On Sat, May 10, 2025 at 11:12:49PM +0200, Ingo Schwarze wrote:
> I cannot say yet how this happened, but *if* this was caused by
> an update to xterm(1) from upstream, then that means trusting
> upstream with xterm(1) is not a good idea.

The bug was introduced (intentionally?) in xterm 391:

  https://invisible-island.net/xterm/xterm.log.html#xterm_391

I've downloaded, compiled and tested 390 and 391 versions.  I could
reproduce the bug with 391 version, xtrem-390 works as expected.  Test
with xterm-390:

  $ printf '\x9bc\n'
  �c


-- 
Walter