Master controller can only send updates and can push the config to other local controllers.
However config would be the same between master and local in terms of ap-group config, VAP profiles, ssid, aaa profiles etc. Anything switch specfic config like VLAN based config or routing based config would be individual to the controller will not synch between master and local.
Master controller holds the config all the sites and even local controller holds the config of all sites however master maintan the database sync, owns the config to pushed, maintains the AP database, WMS database, whitelist, etc and those jobs are not owned by local as they take the command whateven given to them by master. As i said earlier, all your switch specfic config of vlans etc would be independent and wouldnt sync between controllers.
Thank you,
Sriram