anchor.diff:  
   Quarkus provides `create-extension` Maven Mojo to initialize your extension project.
   
  -[source, shell]
  +[source, shell, subs=attributes+]
   ----
   $ mvn io.quarkus:quarkus-maven-plugin:{quarkus-version}:create-extension -N \
       -DgroupId=org.acme \ #<1>
  
positive.code: 
  Run the application and notice the `Install Features` list contains the `quarkus-greeting` extension.
  
  [source, shell]
  ----
  $ mvn clean compile quarkus:dev
  [INFO] Scanning for projects...
  
negative.code: 
  Your extension is a multi-module project. So let's start by checking out the parent POM at `./quarkus-greeting/pom.xml`.
  
  [source, xml, subs=attributes+]
  ----
  <?xml version="1.0" encoding="UTF-8"?>
  <project xmlns="http://maven.apache.org/POM/4.0.0"
  