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.

9 files changed, 30 insertions, 0 deletions

diff --git a/subprojects/language-model/META-INF/MANIFEST.MF.license b/subprojects/language-model/META-INF/MANIFEST.MF.license
new file mode 100644
index 00000000..e5db6ccd
--- /dev/null
+++ b/subprojects/language-model/META-INF/MANIFEST.MF.license
@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+
+SPDX-License-Identifier: EPL-2.0
diff --git a/subprojects/language-model/build.gradle.kts b/subprojects/language-model/build.gradle.kts
index 12b6bc13..4f15e5e6 100644
--- a/subprojects/language-model/build.gradle.kts
+++ b/subprojects/language-model/build.gradle.kts
@@ -1,3 +1,9 @@
+/*
+ * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+
 import tools.refinery.gradle.utils.SonarPropertiesUtils
 
 plugins {
diff --git a/subprojects/language-model/build.properties b/subprojects/language-model/build.properties
index 65dfc7c4..9b9859ff 100644
--- a/subprojects/language-model/build.properties
+++ b/subprojects/language-model/build.properties
@@ -1,4 +1,6 @@
+# SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
 #
+# SPDX-License-Identifier: EPL-2.0
 
 bin.includes = .,\
                src/main/resources/model/,\
diff --git a/subprojects/language-model/plugin.properties b/subprojects/language-model/plugin.properties
index c4fb7e23..c410feb7 100644
--- a/subprojects/language-model/plugin.properties
+++ b/subprojects/language-model/plugin.properties
@@ -1,4 +1,6 @@
+# SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
 #
+# SPDX-License-Identifier: EPL-2.0
 
 pluginName = tools.refinery.language.model
 providerName = refinery.tools
diff --git a/subprojects/language-model/plugin.xml b/subprojects/language-model/plugin.xml
index 4ca005a8..ef1e21f4 100644
--- a/subprojects/language-model/plugin.xml
+++ b/subprojects/language-model/plugin.xml
@@ -2,6 +2,9 @@
 <?eclipse version="3.0"?>
 
 <!--
+  SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+
+  SPDX-License-Identifier: EPL-2.0
 -->
 
 <plugin>
diff --git a/subprojects/language-model/problem.aird.license b/subprojects/language-model/problem.aird.license
new file mode 100644
index 00000000..e5db6ccd
--- /dev/null
+++ b/subprojects/language-model/problem.aird.license
@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+
+SPDX-License-Identifier: EPL-2.0
diff --git a/subprojects/language-model/src/main/java/tools/refinery/language/model/GenerateProblemModel.mwe2 b/subprojects/language-model/src/main/java/tools/refinery/language/model/GenerateProblemModel.mwe2
index 15198d69..074b6b71 100644
--- a/subprojects/language-model/src/main/java/tools/refinery/language/model/GenerateProblemModel.mwe2
+++ b/subprojects/language-model/src/main/java/tools/refinery/language/model/GenerateProblemModel.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.model.GenerateProblemModel
 
 Workflow {
diff --git a/subprojects/language-model/src/main/resources/model/problem.ecore.license b/subprojects/language-model/src/main/resources/model/problem.ecore.license
new file mode 100644
index 00000000..e5db6ccd
--- /dev/null
+++ b/subprojects/language-model/src/main/resources/model/problem.ecore.license
@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+
+SPDX-License-Identifier: EPL-2.0
diff --git a/subprojects/language-model/src/main/resources/model/problem.genmodel.license b/subprojects/language-model/src/main/resources/model/problem.genmodel.license
new file mode 100644
index 00000000..e5db6ccd
--- /dev/null
+++ b/subprojects/language-model/src/main/resources/model/problem.genmodel.license
@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+
+SPDX-License-Identifier: EPL-2.0