diff --git a/cli/internal/plugin/discover.go b/cli/internal/plugin/discover.go
index 7263e3237..f59cdce6b 100644
--- a/cli/internal/plugin/discover.go
+++ b/cli/internal/plugin/discover.go
@@ -1,3 +1,19 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package plugin
 
 import (
diff --git a/cli/internal/plugin/discover_test.go b/cli/internal/plugin/discover_test.go
index f1c458ecd..948171a7b 100644
--- a/cli/internal/plugin/discover_test.go
+++ b/cli/internal/plugin/discover_test.go
@@ -1,3 +1,19 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package plugin_test
 
 import (
diff --git a/cli/internal/plugin/invoke.go b/cli/internal/plugin/invoke.go
index 17bf8480b..b5235dff6 100644
--- a/cli/internal/plugin/invoke.go
+++ b/cli/internal/plugin/invoke.go
@@ -1,3 +1,19 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package plugin
 
 import (
diff --git a/cli/internal/plugin/invoke_test.go b/cli/internal/plugin/invoke_test.go
index d3ca93ffe..96855157d 100644
--- a/cli/internal/plugin/invoke_test.go
+++ b/cli/internal/plugin/invoke_test.go
@@ -1,3 +1,19 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package plugin_test
 
 import (
diff --git a/cli/internal/plugin/plugin.go b/cli/internal/plugin/plugin.go
index b6acae77c..f5436811f 100644
--- a/cli/internal/plugin/plugin.go
+++ b/cli/internal/plugin/plugin.go
@@ -1,3 +1,19 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package plugin
 
 import "errors"
diff --git a/converters/nvidia/tests/fixtures/sales.gsf.yaml b/converters/nvidia/tests/fixtures/sales.gsf.yaml
index 97c1479bf..be3d5da58 100644
--- a/converters/nvidia/tests/fixtures/sales.gsf.yaml
+++ b/converters/nvidia/tests/fixtures/sales.gsf.yaml
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 data_layer:
   databases:
   - id: 7667e398-1abf-5314-9d5d-f91a6d5d0887
diff --git a/converters/nvidia/tests/fixtures/sales.ossie.yaml b/converters/nvidia/tests/fixtures/sales.ossie.yaml
index 4e0bd6f2a..442c159b2 100644
--- a/converters/nvidia/tests/fixtures/sales.ossie.yaml
+++ b/converters/nvidia/tests/fixtures/sales.ossie.yaml
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 version: 0.2.0.dev0
 semantic_model:
 - name: sales
diff --git a/converters/sigma/pyproject.toml b/converters/sigma/pyproject.toml
index 75d4c0647..025ed08c0 100644
--- a/converters/sigma/pyproject.toml
+++ b/converters/sigma/pyproject.toml
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 [build-system]
 requires = ["hatchling"]
 build-backend = "hatchling.build"
diff --git a/converters/sigma/src/ossie_sigma/__init__.py b/converters/sigma/src/ossie_sigma/__init__.py
index 7fcc602e8..98ca5859a 100644
--- a/converters/sigma/src/ossie_sigma/__init__.py
+++ b/converters/sigma/src/ossie_sigma/__init__.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 from ossie_sigma.ossie_to_sigma import OssieToSigmaConverter
 from ossie_sigma.sigma_to_ossie import SigmaToOssieConverter
 
diff --git a/converters/sigma/src/ossie_sigma/cli.py b/converters/sigma/src/ossie_sigma/cli.py
index 15dc9ac92..55e866629 100644
--- a/converters/sigma/src/ossie_sigma/cli.py
+++ b/converters/sigma/src/ossie_sigma/cli.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """CLI entry point for the ossie-sigma converter.
 
 Usage:
diff --git a/converters/sigma/src/ossie_sigma/converter_issues.py b/converters/sigma/src/ossie_sigma/converter_issues.py
index 2a04005eb..b6c5dfba5 100644
--- a/converters/sigma/src/ossie_sigma/converter_issues.py
+++ b/converters/sigma/src/ossie_sigma/converter_issues.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 from dataclasses import dataclass
 from enum import Enum
 from typing import Generic, List, TypeVar
diff --git a/converters/sigma/src/ossie_sigma/expression_utils.py b/converters/sigma/src/ossie_sigma/expression_utils.py
index 78eee4cb6..da73b62e4 100644
--- a/converters/sigma/src/ossie_sigma/expression_utils.py
+++ b/converters/sigma/src/ossie_sigma/expression_utils.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """Shared helpers for building/reading Ossie ``OssieExpression`` values from Sigma formulas."""
 
 from __future__ import annotations
diff --git a/converters/sigma/src/ossie_sigma/ossie_to_sigma.py b/converters/sigma/src/ossie_sigma/ossie_to_sigma.py
index f3532617f..ef4d639e8 100644
--- a/converters/sigma/src/ossie_sigma/ossie_to_sigma.py
+++ b/converters/sigma/src/ossie_sigma/ossie_to_sigma.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """Apache Ossie (OssieDocument) -> Sigma data model spec (JSON)."""
 
 from __future__ import annotations
diff --git a/converters/sigma/src/ossie_sigma/sigma_formula.py b/converters/sigma/src/ossie_sigma/sigma_formula.py
index b5cc65380..c3060588a 100644
--- a/converters/sigma/src/ossie_sigma/sigma_formula.py
+++ b/converters/sigma/src/ossie_sigma/sigma_formula.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """A parser and SQL renderer for Sigma's spreadsheet-style formula language.
 
 Sigma data model column and metric formulas look like ``Sum([Orders/Amount])`` or
diff --git a/converters/sigma/src/ossie_sigma/sigma_to_ossie.py b/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
index b2fff4bf5..b26917b09 100644
--- a/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
+++ b/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """Sigma data model spec (JSON) -> Apache Ossie (OssieDocument)."""
 
 from __future__ import annotations
diff --git a/converters/sigma/src/ossie_sigma/spec_keys.py b/converters/sigma/src/ossie_sigma/spec_keys.py
index 67b60ca2e..453f58524 100644
--- a/converters/sigma/src/ossie_sigma/spec_keys.py
+++ b/converters/sigma/src/ossie_sigma/spec_keys.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """Sigma data-model-spec keys shared by both conversion directions.
 
 Kept in one place so the set of model-level keys captured into
diff --git a/converters/sigma/tests/__init__.py b/converters/sigma/tests/__init__.py
index e69de29bb..13a83393a 100644
--- a/converters/sigma/tests/__init__.py
+++ b/converters/sigma/tests/__init__.py
@@ -0,0 +1,16 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
diff --git a/converters/sigma/tests/helpers.py b/converters/sigma/tests/helpers.py
index 56b3c9588..2ee80913b 100644
--- a/converters/sigma/tests/helpers.py
+++ b/converters/sigma/tests/helpers.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 import json
 from pathlib import Path
 from typing import Any
diff --git a/converters/sigma/tests/test_ossie_to_sigma.py b/converters/sigma/tests/test_ossie_to_sigma.py
index b92040451..840adbf3d 100644
--- a/converters/sigma/tests/test_ossie_to_sigma.py
+++ b/converters/sigma/tests/test_ossie_to_sigma.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 from pathlib import Path
 
 import yaml
diff --git a/converters/sigma/tests/test_roundtrip.py b/converters/sigma/tests/test_roundtrip.py
index 0887a64c4..11b389901 100644
--- a/converters/sigma/tests/test_roundtrip.py
+++ b/converters/sigma/tests/test_roundtrip.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 """End-to-end round trips through the same serialization boundary the CLI uses
 (OssieDocument -> YAML text -> re-parsed OssieDocument), for every fixture."""
 
diff --git a/converters/sigma/tests/test_sigma_formula.py b/converters/sigma/tests/test_sigma_formula.py
index 931b2bdf9..36b34fe9f 100644
--- a/converters/sigma/tests/test_sigma_formula.py
+++ b/converters/sigma/tests/test_sigma_formula.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 import pytest
 
 from ossie_sigma.sigma_formula import (
diff --git a/converters/sigma/tests/test_sigma_to_ossie.py b/converters/sigma/tests/test_sigma_to_ossie.py
index 9e848f8a4..f0c9ba7bd 100644
--- a/converters/sigma/tests/test_sigma_to_ossie.py
+++ b/converters/sigma/tests/test_sigma_to_ossie.py
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
 import pytest
 from ossie import OssieDialect