diff --git a/Build/CMakeLists.txt b/Build/CMakeLists.txt
new file mode 100644
index 0000000000000000000000000000000000000000..8022f587afc40613d27c092c3cd7392116007700
--- /dev/null
+++ b/Build/CMakeLists.txt
@@ -0,0 +1,7 @@
+#
+# This is a dummy CMakeLists.txt file, only here to make the CI system
+# categorise modifications in this directory correctly.
+#
+# It should not have any actual code, as nothing in this directory should
+# actually be built.
+#
diff --git a/Projects/Athena/package_filters.txt b/Projects/Athena/package_filters.txt
index b30a82b322938960613048caa0deb0b6f42d8048..412009d42f4813b2fb8b46649302e533002e87f7 100644
--- a/Projects/Athena/package_filters.txt
+++ b/Projects/Athena/package_filters.txt
@@ -1,49 +1,54 @@
+#
 # Package filtering rules for the Athena project build.
 #
+
+# Technical packages that should not show up in packages.txt:
+- CI
+- Build
+
 # Only pick up a few packages from the External directory:
-+External/AtlasDataArea
-+External/pyAMI
-+External/FWDet/TwissFiles
-+External/Herwigpp
-+External/AtlasMKL
--External
++ External/AtlasDataArea
++ External/pyAMI
++ External/FWDet/TwissFiles
++ External/Herwigpp
++ External/AtlasMKL
+- External/.*
+
 # Only pick up the RunTime packages from Projects:
-+Projects/.*RunTime
--Projects
++ Projects/.*RunTime
+- Projects/.*
+
 # Remove HLT packages
--HLT
--Trigger/TrigValidation/TrigP1Test
+- HLT/.*
+- Trigger/TrigValidation/TrigP1Test
 
 # Offload service has build problems
--External/APEGlue
--Offloading
+- External/APEGlue
+- Offloading/.*
 
 # Temporary VP1 compilation issues
--graphics/VP1
+- graphics/VP1/.*
 
 # Some analysis packages that are not part of Athena
--AsgExternal/Asg_Test
--Control/AthLinksSA
--PhysicsAnalysis/D3PDTools/EventLoop
--PhysicsAnalysis/AnalysisCommon/CPAnalysisExamples
--PhysicsAnalysis/AnalysisCommon/PMGTools
--PhysicsAnalysis/D3PDTools/EventLoop
--PhysicsAnalysis/D3PDTools/EventLoopAlgs
--PhysicsAnalysis/D3PDTools/EventLoopGrid
--PhysicsAnalysis/D3PDTools/MultiDraw
--PhysicsAnalysis/D3PDTools/SampleHandler
--PhysicsAnalysis/ElectronPhotonID/PhotonEfficiencyCorrection
--PhysicsAnalysis/ElectronPhotonID/PhotonVertexSelection
--PhysicsAnalysis/HiggsPhys/Run2/HZZ/Tools/ZMassConstraint
--PhysicsAnalysis/JetPhys/SemileptonicCorr
--PhysicsAnalysis/SUSYPhys/SUSYTools
--PhysicsAnalysis/TauID/DiTauMassTools
--PhysicsAnalysis/TauID/TauCorrUncert
--PhysicsAnalysis/TopPhys/QuickAna
--PhysicsAnalysis/TrackingID/InDetTrackSystematicsTools
--Reconstruction/Jet/JetAnalysisTools/JetTileCorrection
--Reconstruction/Jet/JetJvtEfficiency
--Reconstruction/Jet/JetReclustering
--Reconstruction/Jet/JetAnalysisTools/JetTileCorrection
--Trigger/TrigAnalysis/TrigMuonEfficiency
--Trigger/TrigAnalysis/TrigTauAnalysis/TrigTauMatching
+- AsgExternal/Asg_Test
+- Control/AthLinksSA
+- PhysicsAnalysis/AnalysisCommon/CPAnalysisExamples
+- PhysicsAnalysis/AnalysisCommon/PMGTools
+- PhysicsAnalysis/D3PDTools/EventLoop.*
+- PhysicsAnalysis/D3PDTools/MultiDraw
+- PhysicsAnalysis/D3PDTools/SampleHandler
+- PhysicsAnalysis/ElectronPhotonID/PhotonEfficiencyCorrection
+- PhysicsAnalysis/ElectronPhotonID/PhotonVertexSelection
+- PhysicsAnalysis/HiggsPhys/Run2/HZZ/Tools/ZMassConstraint
+- PhysicsAnalysis/JetPhys/SemileptonicCorr
+- PhysicsAnalysis/SUSYPhys/SUSYTools
+- PhysicsAnalysis/TauID/DiTauMassTools
+- PhysicsAnalysis/TauID/TauCorrUncert
+- PhysicsAnalysis/TopPhys/QuickAna
+- PhysicsAnalysis/TrackingID/InDetTrackSystematicsTools
+- Reconstruction/Jet/JetAnalysisTools/JetTileCorrection
+- Reconstruction/Jet/JetJvtEfficiency
+- Reconstruction/Jet/JetReclustering
+- Reconstruction/Jet/JetAnalysisTools/JetTileCorrection
+- Trigger/TrigAnalysis/TrigMuonEfficiency
+- Trigger/TrigAnalysis/TrigTauAnalysis/TrigTauMatching