On 7/10/2024 12:33 AM, Michael Albinus via Bug reports for GNU Emacs, 
the Swiss army knife of text editors wrote:
> Tramp ought to support signal-process (and interrupt-process). See
> optional argument REMOTE of signal-process.
> 
> Best regards, Michael.

Ok, I figured out why I thought Tramp didn't support 'signal-process'. 
Elsewhere in Emacs, you can provide the signal to use like so: 
'SIGKILL'. However, Tramp's 'tramp-signal-process' passes the name 
directly to the POSIX "kill" command, which expects the "SIG" to be 
removed. Here's a patch which does this.