Clarify licensing through REUSE annotations.

 - Manual: GFDL-1.3-or-later
 - Library: LGPL-3.0-or-later
 - Examples: GPL-3.0-or-later

Change-Id: I1d1bfede7ba51c4043f8d7e572aa88b42cc8bacf
diff --git a/jgvariant-core/pom.xml b/jgvariant-core/pom.xml
index 2dea553..2ddf2c4 100644
--- a/jgvariant-core/pom.xml
+++ b/jgvariant-core/pom.xml
@@ -1,4 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+
+SPDX-License-Identifier: LGPL-3.0-or-later
+-->
+
 <project
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"
   xmlns="http://maven.apache.org/POM/4.0.0"
diff --git a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Decoder.java b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Decoder.java
index 3beb247..1dbd1fa 100644
--- a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Decoder.java
+++ b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Decoder.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 package eu.mulk.jgvariant.core;
 
 import static java.nio.ByteOrder.LITTLE_ENDIAN;
diff --git a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Signature.java b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Signature.java
index c697730..d61b9d1 100644
--- a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Signature.java
+++ b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Signature.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 package eu.mulk.jgvariant.core;
 
 import java.nio.ByteBuffer;
diff --git a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Variant.java b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Variant.java
index d9e13dd..47aa30e 100644
--- a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Variant.java
+++ b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/Variant.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 package eu.mulk.jgvariant.core;
 
 import org.apiguardian.api.API;
diff --git a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/package-info.java b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/package-info.java
index 1754096..a1e0a20 100644
--- a/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/package-info.java
+++ b/jgvariant-core/src/main/java/eu/mulk/jgvariant/core/package-info.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 /**
  * Provides {@link eu.mulk.jgvariant.core.Decoder}, the foundational class for <a
  * href="https://docs.gtk.org/glib/struct.Variant.html">GVariant</a> parsing.
diff --git a/jgvariant-core/src/main/java/module-info.java b/jgvariant-core/src/main/java/module-info.java
index ab5730e..4df8acd 100644
--- a/jgvariant-core/src/main/java/module-info.java
+++ b/jgvariant-core/src/main/java/module-info.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 /**
  * Provides a parser for the <a href="https://docs.gtk.org/glib/struct.Variant.html">GVariant</a>
  * serialization format.
diff --git a/jgvariant-core/src/test/java/eu/mulk/jgvariant/core/DecoderTest.java b/jgvariant-core/src/test/java/eu/mulk/jgvariant/core/DecoderTest.java
index 8c78692..3f826be 100644
--- a/jgvariant-core/src/test/java/eu/mulk/jgvariant/core/DecoderTest.java
+++ b/jgvariant-core/src/test/java/eu/mulk/jgvariant/core/DecoderTest.java
@@ -1,3 +1,7 @@
+// SPDX-FileCopyrightText: © 2021 Matthias Andreas Benkard <code@mail.matthias.benkard.de>
+//
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
 package eu.mulk.jgvariant.core;
 
 import static java.nio.ByteOrder.BIG_ENDIAN;