Define a unique configuration for CondDBESSource including FroNTier servlets for fetching Condition payloads in CondCore/ESSources/python/CondDBESSource_cfi.py. This is then loaded in Configuration/StandardSequences/python/FrontierConditions_GlobalTag_cfi.py and cloned in RecoTauTag/Configuration/python/loadRecoTauTagMVAsFromPrepDB_cfi.py.