In a somewhat silent change, WineHQ has changed their repository keys and changed the names of the .key filenames.
Originally, this was the apt key adding procedure:
wget -nc https://dl.winehq.org/wine-builds/Release.key
sudo apt-key add Release.key
Now, it’s this:
wget -nc https://dl.winehq.org/wine-builds/winehq.key
sudo apt-key add winehq.key
Unfortunately, Release.key still exists on the server without a redirect so people could be unsuspectingly getting the old key if following older Wine guides. You HAVE to get winehq.key from now on.
Let your fellow Wine is not an emulator friends know.