chore: add copyright headers

Make sure we obey the REUSE (https://reuse.software) specification and the
origin, copyright owner, and license of all files are clearly marked.

The whole project is under the EPL-2.0, except for trivial files where copyright
is not applicable that are marked with the CC0-1.0 license. Moreover, code
included from third parties is also available under the respective license.

chore: add CONTRIBUTORS.md

List all authors and supporting organizations in accordance with the REUSE
specification.

32 files changed, 167 insertions, 1 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/GenerateProblem.mwe2 b/subprojects/language/src/main/java/tools/refinery/language/GenerateProblem.mwe2
index 21ff456e..d8d89173 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/GenerateProblem.mwe2
+++ b/subprojects/language/src/main/java/tools/refinery/language/GenerateProblem.mwe2
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 module tools.refinery.language.GenerateProblem
 
 import org.eclipse.xtext.xtext.generator.*
@@ -55,7 +60,7 @@ Workflow {
                         }
                         webSupport = {
                                 // We only generate the {@code AbstractProblemWebModule},
-                                // because we write our own integration code for CodeMirror 6. 
+                                // because we write our own integration code for CodeMirror 6.
                                 framework = 'codemirror'
                                 generateHtmlExample = false
                                 generateJettyLauncher = false
diff --git a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
index 187ebf1f..9e330347 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
+++ b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 grammar tools.refinery.language.Problem with org.eclipse.xtext.common.Terminals
 
 import "http://www.eclipse.org/emf/2002/Ecore" as ecore
diff --git a/subprojects/language/src/main/java/tools/refinery/language/ProblemRuntimeModule.java b/subprojects/language/src/main/java/tools/refinery/language/ProblemRuntimeModule.java
index 5efcdc81..2636a8ee 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/ProblemRuntimeModule.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/ProblemRuntimeModule.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.25.0
  */
 package tools.refinery.language;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/ProblemStandaloneSetup.java b/subprojects/language/src/main/java/tools/refinery/language/ProblemStandaloneSetup.java
index 41c96114..639d6778 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/ProblemStandaloneSetup.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/ProblemStandaloneSetup.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.25.0
  */
 package tools.refinery.language;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/conversion/ProblemValueConverterService.java b/subprojects/language/src/main/java/tools/refinery/language/conversion/ProblemValueConverterService.java
index 508688ed..afbc367e 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/conversion/ProblemValueConverterService.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/conversion/ProblemValueConverterService.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.conversion;
 
 import org.eclipse.xtext.common.services.DefaultTerminalConverters;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/conversion/UpperBoundValueConverter.java b/subprojects/language/src/main/java/tools/refinery/language/conversion/UpperBoundValueConverter.java
index be0d15ad..4886757d 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/conversion/UpperBoundValueConverter.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/conversion/UpperBoundValueConverter.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.conversion;
 
 import org.eclipse.xtext.conversion.ValueConverterException;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java b/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
index 797535ea..55a5ac20 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/formatting2/ProblemFormatter.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.26.0.M2
  */
 package tools.refinery.language.formatting2;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/naming/NamingUtil.java b/subprojects/language/src/main/java/tools/refinery/language/naming/NamingUtil.java
index e959be74..1647d4e7 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/naming/NamingUtil.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/naming/NamingUtil.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.naming;
 
 import java.util.regex.Pattern;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/naming/ProblemQualifiedNameConverter.java b/subprojects/language/src/main/java/tools/refinery/language/naming/ProblemQualifiedNameConverter.java
index 5453906f..74b4e208 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/naming/ProblemQualifiedNameConverter.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/naming/ProblemQualifiedNameConverter.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.naming;
 
 import org.eclipse.xtext.naming.IQualifiedNameConverter;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/IdentifierTokenProvider.java b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/IdentifierTokenProvider.java
index ab133a90..306a86fc 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/IdentifierTokenProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/IdentifierTokenProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.parser.antlr;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
index 0b4e7185..5b91a6cc 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.29.0.M2
  */
 package tools.refinery.language.parser.antlr;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/TokenSourceInjectingProblemParser.java b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/TokenSourceInjectingProblemParser.java
index 0cdd38d8..fe4c0bc7 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/TokenSourceInjectingProblemParser.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/TokenSourceInjectingProblemParser.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.parser.antlr;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java b/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
index 6176b0c4..07c5da41 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/DerivedVariableComputer.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ImplicitVariableScope.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ImplicitVariableScope.java
index b0ac2ab6..e97c8287 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ImplicitVariableScope.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ImplicitVariableScope.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import org.eclipse.emf.ecore.EObject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/NodeNameCollector.java b/subprojects/language/src/main/java/tools/refinery/language/resource/NodeNameCollector.java
index 419be0d3..e5deca4d 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/NodeNameCollector.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/NodeNameCollector.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import com.google.common.collect.ImmutableSet;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemDerivedStateComputer.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemDerivedStateComputer.java
index 8d3a552a..b145ef27 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemDerivedStateComputer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemDerivedStateComputer.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemLocationInFileProvider.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemLocationInFileProvider.java
index df822987..1fe2df89 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemLocationInFileProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemLocationInFileProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import org.eclipse.emf.ecore.EObject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
index 1a0b73a8..630be379 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import org.eclipse.emf.ecore.EObject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ReferenceCounter.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ReferenceCounter.java
index ca20325e..f1be55ee 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ReferenceCounter.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ReferenceCounter.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.resource;
 
 import java.util.HashMap;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
index b749154c..4d2dd772 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemGlobalScopeProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.scoping;
 
 import java.util.LinkedHashSet;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
index 61883f0e..229960a0 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemLocalScopeProvider.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.scoping;
 
 import java.util.List;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
index 3ab07496..cf099aba 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/scoping/ProblemScopeProvider.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.25.0
  */
 package tools.refinery.language.scoping;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/serializer/PreferShortAssertionsProblemSemanticSequencer.java b/subprojects/language/src/main/java/tools/refinery/language/serializer/PreferShortAssertionsProblemSemanticSequencer.java
index 27ce1521..b9cafbc2 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/serializer/PreferShortAssertionsProblemSemanticSequencer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/serializer/PreferShortAssertionsProblemSemanticSequencer.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.serializer;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/BuiltinSymbols.java b/subprojects/language/src/main/java/tools/refinery/language/utils/BuiltinSymbols.java
index d3777cd3..c8c7fd4a 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/BuiltinSymbols.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/BuiltinSymbols.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import tools.refinery.language.model.problem.*;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/CollectedSymbols.java b/subprojects/language/src/main/java/tools/refinery/language/utils/CollectedSymbols.java
index b5682f32..e4e4d07a 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/CollectedSymbols.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/CollectedSymbols.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import java.util.Map;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/ContainmentRole.java b/subprojects/language/src/main/java/tools/refinery/language/utils/ContainmentRole.java
index 708e10a9..a43c7dfe 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/ContainmentRole.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/ContainmentRole.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import tools.refinery.language.model.problem.PredicateKind;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/NodeInfo.java b/subprojects/language/src/main/java/tools/refinery/language/utils/NodeInfo.java
index c8f47653..0fa7a454 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/NodeInfo.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/NodeInfo.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 public record NodeInfo(String name, boolean individual) {
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
index b8200919..738a0896 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
index 1e5164d3..9486dc2a 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import org.eclipse.emf.common.util.URI;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/RelationInfo.java b/subprojects/language/src/main/java/tools/refinery/language/utils/RelationInfo.java
index 2253d257..1c46fe72 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/RelationInfo.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/RelationInfo.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import tools.refinery.language.model.problem.*;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/SymbolCollector.java b/subprojects/language/src/main/java/tools/refinery/language/utils/SymbolCollector.java
index 65167ed6..a4ea1113 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/SymbolCollector.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/SymbolCollector.java
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
 package tools.refinery.language.utils;
 
 import com.google.inject.Inject;
diff --git a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
index 659d882c..88d50c5b 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
@@ -1,4 +1,10 @@
 /*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
+/*
  * generated by Xtext 2.25.0
  */
 package tools.refinery.language.validation;