how do i find a GPG key when missing for an application etc

"W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://dl.winehq.org/wine-builds/ubuntu lunar InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F"



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Here is the whole bash page that made me aware i was missing what i needed for my version (lunar lobster) and then the fall back is also not able to be used because of abscence of gpg key.

Remedy=?

thanks anyone.....fyi out to get coffee, back soon;if i dont reply for a while.