Do you know of a Wireshark filter that will reveal this on Ubuntu? What you're saying doesn't sound credible, but to incentivize, here's the bet:

If you can provide a Wireshark filter that will show a certificate check on a vanilla Ubuntu 20.04 system when the following commands are executed in a bash shell, then I will donate $25 to a charity of your choice. Commands follow:

    cat <<HEREDOC >/tmp/file.c
    #include <stdio.h>

    int main() {
      printf("Hello World");
      return 0;
    }
    HEREDOC
    gcc /tmp/file.c -o /tmp/app
    /tmp/app