Public key for verifying emacs sources?

[Steve Revilak]

I'm having trouble verifying the pgp signature of the emacs 27.2
sources.  I've downloaded

 https://ftp.gnu.org/gnu/emacs/emacs-27.2.tar.xz, and
 https://ftp.gnu.org/gnu/emacs/emacs-27.2.tar.xz.sig

I'd like to verify the tar.xz file before building, but I'm running
into this:

 $ gpg --verify emacs-27.2.tar.xz.sig
 gpg: assuming signed data in 'emacs-27.2.tar.xz'
 gpg: Signature made Thu 25 Mar 2021 07:53:08 AM EDT
 gpg:                using RSA key 0x91C1262F01EB8D39
 gpg: Can't check signature: No public key

And the keyserver I normally use doesn't know about key
0x91C1262F01EB8D39:

 $ gpg --keyserver keys.openpgp.org --recv-key 0x91C1262F01EB8D39
 gpg: keyserver receive failed: No data

Where can I find a copy of the signing key, so I can verify the source
distribution I've downloaded?

Steve

signature.asc
Description: Digital signature