GPG: find secret-keyfile that matches my public-key

When I create a keypair with gpg, then it stores the secret key inside of ~/.gnupg/private-keys-v1.d It stores the public-key inside of a keyring-file - I can name it or it uses the default-location. If I have a look (*--list-public-keys* and *--list-secret-keys*) at my public and secret-keys I can see what pair matches. The 40 character string/hash in the output is the same for both. The file of the secret-key is different to this string. It is also 40 chars long, but different. How do I find out what secret-key file matches my public-key?? Using gpg 2.2.40 on Debian 12.