They spray a cleaner in and blow the assembly out then add a drop or 2 of oil.
And i can do the exact same thing with a Knight bolt and trigger so i fail to see how a break action is easier to clean. Ive owned both styles of MLs. Both are very simple to clean if you have the 209 tolerance (head space) set correctly. Its pretty simple to do with a Knight,,,Just use a Win209 or shim the primer pocket for the primer of your choice.
The breach will stay virtually spotless
Now with the breach, bolt and trigger out of the equation we only have a barrel/breach plug left. Never seen any difference in cleaning one barrel over another. The difference in a toolless plug vs a plug needing a socket is so small i would rather have a better designed plug like the Lehigh, Savage or Omega plug.