Location of Emacs 29 in a Debian 12 system

I have installed Emacs 28.2 in Debian 12. I have also installed Emacs 29.1 from bookworm-backports.

~$ aptitude show emacs
Package: emacs                    
Version: 1:29.1+1-5~bpo12+1
State: installed
Automatically installed: no
Priority: optional
Section: editors
Maintainer: Rob Browning 
Architecture: all
Uncompressed Size: 52.2 k
Depends: emacs-gtk (>= 1:27.1) | emacs-pgtk (>= 1:27.1) | emacs-lucid (>= 1:27.1) | emacs-nox (>= 1:27.1)
Provided by: emacs-gtk (1:28.2+1-15), emacs-gtk (1:29.1+1-5~bpo12+1), emacs-lucid (1:28.2+1-15), emacs-lucid (1:29.1+1-5~bpo12+1),
             emacs-nox (1:28.2+1-15), emacs-nox (1:29.1+1-5~bpo12+1), emacs-pgtk (1:29.1+1-5~bpo12+1)
Description: GNU Emacs editor (metapackage)
 GNU Emacs is the extensible self-documenting text editor. This is a metapackage that will always depend on the latest recommended
 Emacs variant (currently emacs-gtk).
Homepage: https://www.gnu.org/software/emacs/ 
Tags: devel::editor, role::dummy, role::metapackage, role::program, suite::emacs, suite::gnu, use::editing

I wish to point my system to use Emacs 29.1. I could remove the 28.2 package but I wish to experiment with both before deciding which one to use. I have seen update-alternatives which allows us to use multiple versions of the same program. How do I find out the location of Emacs 29.1 file so that I can use it with update-alternatives ?