Much to my confusion the openSUSE source repository containing debug symbols is not enabled by default, though the repo metadata is present,

matt@feynman:~> zypper lr repo-debug
Alias          : repo-debug                                             
Name           : openSUSE-Tumbleweed-Debug                              
URI            : http://download.opensuse.org/debug/tumbleweed/repo/oss/
Enabled        : No                                   
GPG Check      : ----                                 
Priority       : 99                                                     
Auto-refresh   : On                                                     
Keep Packages  : Off                                                    
Type           : yast2                                                  
GPG Key URI    :                                                        
Path Prefix    : /                                                      
Parent Service :                                                        
Repo Info Path : /etc/zypp/repos.d/repo-debug.repo                      
MD Cache Path  : /var/cache/zypp/raw/repo-debug                         
Which means that, by default, debug packages will not be returned in your zypper search results. You can enable it so that the debug packages are displayed with zypper search like so,

matt@feynman:~> sudo zypper mr -e repo-debug
Repository 'repo-debug' has been successfully enabled.