this certificate is not present in my keychain (at least, so it seems to me).
my app is present both on iOS and Macos
to be clear, I know it is not a "Mac certificate".
someone can help me?
here an image
Distribution cert is what you use to sign an app for production in most cases. Development cert is used for building/developing apps and testing.
First check which cert is being used to sign your ipa
Payload
folder
unzip -q <your_app>.ipa
security cms -D -i Payload/<your_app>.app/embedded.mobileprovision > <your_app>.plist
/usr/libexec/PlistBuddy -c "print Name" <your_app>.plist
/usr/libexec/PlistBuddy -c "print ExpirationDate" <your_app>.plist
Depending on the outcome of above, can decide whether the Development cert is needed or not.
how can I discover what happens when it expires?
You would need to re-sign your ipa if this happens