/usr/share/doc/gradle/examples/signing/ is in gradle-doc 3.4.1-7ubuntu1.
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/usr/share/doc/gradle/examples/signing/conditional/
/usr/share/doc/gradle/examples/signing/conditional/build.gradle
/usr/share/doc/gradle/examples/signing/conditional/src/
/usr/share/doc/gradle/examples/signing/conditional/src/main/
/usr/share/doc/gradle/examples/signing/conditional/src/main/java/
/usr/share/doc/gradle/examples/signing/conditional/src/main/java/Sample.java
/usr/share/doc/gradle/examples/signing/conditional/src/main/resources/
/usr/share/doc/gradle/examples/signing/conditional/src/main/resources/sample.txt
/usr/share/doc/gradle/examples/signing/maven/
/usr/share/doc/gradle/examples/signing/maven/build.gradle
/usr/share/doc/gradle/examples/signing/maven/gradle.properties
/usr/share/doc/gradle/examples/signing/maven/secKeyRingFile.gpg
/usr/share/doc/gradle/examples/signing/maven/src/
/usr/share/doc/gradle/examples/signing/maven/src/main/
/usr/share/doc/gradle/examples/signing/maven/src/main/java/
/usr/share/doc/gradle/examples/signing/maven/src/main/java/Sample.java
/usr/share/doc/gradle/examples/signing/maven/src/main/resources/
/usr/share/doc/gradle/examples/signing/maven/src/main/resources/sample.txt
/usr/share/doc/gradle/examples/signing/tasks/
/usr/share/doc/gradle/examples/signing/tasks/build.gradle
/usr/share/doc/gradle/examples/signing/tasks/secKeyRingFile.gpg
/usr/share/doc/gradle/examples/signing/tasks/src/
/usr/share/doc/gradle/examples/signing/tasks/src/stuff/
/usr/share/doc/gradle/examples/signing/tasks/src/stuff/hello.txt