I have PGPTools installed, but I thought showing CLI results would be useful here. In case it's not obvious, I'm not sophisticated w/r PGP.
gpg: Signature made Mon Jul 19 11:22:27 2021 PDT
gpg: using RSA key 6694D8DE7BE8EE5631BED9502BD5824B7F9470E6
gpg: key 2BD5824B7F9470E6: new key but contains no user ID - skipped
gpg: Total number processed: 1
gpg: w/o user IDs: 1
gpg: Can't check signature: No public key
~ % gpg --import Downloads/electrum-4.1.5.dmg.ThomasV.asc
gpg: no valid OpenPGP data found.
gpg: Total number processed: 0
% cat Downloads/electrum-4.1.5.dmg.ThomasV.asc
-----BEGIN PGP SIGNATURE-----
iQIzBAABCgAdFiEEZpTY3nvo7lYxvtlQK9WCS3+UcOYFAmD1wuMACgkQK9WCS3+U
[... omitted for brevity ...]
7CDdNAheFpE+xz2F3JSeXrWBHnnYP3k/bVMJwSmSgrvxVRzPpfM=
=K00C
-----END PGP SIGNATURE-----