Here is a list of all namespaces with brief descriptions:

[detail level 12345]

UEAnalysisJets_cfi
UEAnalysisParticles_cfi
UEAnalysisRootple_cfi
UEAnalysisRootpleOnlyMC_cfi
UEAnalysisTracks_cfi
UMNioTask
uncleanedOnlyElectronSequence_cff
uncleanSCRecovery_cfi
UndergroundCosmicMu_cfi
UndergroundCosmicSPLooseMu_cfi
unifiedSCCollection_cfi
uniformMagneticField_cfi
universalConfigTemplate
UnixSignalService_cfi
unpackBuffers-CaloStage1
unpackBuffers-CaloStage2
unpackData-CaloStage1
unpackData-CaloStage2
unpackedPatTrigger_cfi
unpackedTracksAndVertices_cfi
unpacker2007h4_cff
update_db_credential
updateADCToGeV
updateADCToGeV_express
updateADCToGeV_hlt
updateADCToGeV_test
updateHPSPFTaus_cff
updateIntercali
updateIntercali_express
updateIntercali_hlt
updateIntercali_test
upgradeTracking_phase1_cff
upgradeWorkflowComponents
upload_popcon
uploadConditions
uploader
uploadPayloads
UpsEE_7TeV_cfi
UpsEE_8TeV_cfi
UpsEE_cfi
upsilon1sMuMuTrigSettings_cff
Upsilon1SToMuMu_forSTEAM_13TeV_cfi
Upsilon1SToMuMu_forSTEAM_13TeV_TuneCUETP8M1_cfi
Upsilon4sBaBarExample_BpBm_Dstarpipi_D0Kpi_nonres_forSTEAM_13TeV_TuneCUETP8M1_cfi
Upsilon4swithBuToKstarJPsiToMuMu_forSTEAM_13TeV_TuneCUETP8M1_cfi
upsilonToMuMu_EventContent_cff
upsilonToMuMu_HLTPath_cfi
upsilonToMuMu_SkimPath_cff
upsilonToMuMuOutputModuleAODSIM_cfi
UpsMM_7TeV_cfi
UpsMM_8TeV_cfi
UpsMM_8TeV_TuneCUETP8M1_cfi
UpsMM_cfi
UpsMM_EXTRAS_cff
UpsMM_filt_cfi
usedOutput
useReflexToDescribeForGenObject
UserOptions_cff
useSource_custom
UseZeroBField_cff
UTarget_cfi
util
getRunInfo
rrapi
rrClient
Utilities
ReleaseScripts
commentSkipper
commentSkipper
filter
utils
Utils
utils_v2