anchor.diff:  }
   ----
   
  -== Custom Extensions
  +== Adding Custom Extensions
   
   Starting with version 1.5.0 you'll be able to write your own Asciidoctor extensions in Groovy, or any other JVM language
   for that matter. There are several options for you to make it happen.
   
  -=== External Library
  +=== As External Library
   
   This is the most versatile option, as it allows you to reuse the same extension in different projects. An external library
   is just like any other Java/Groovy project. You simply define a dependency using the `asciidoctor` configuration.
  
positive.code: }
  ----
  
  === Inline extensions
  
  The next option is to define extensions directly in the build script.
  This approach is based on the project asciidoctorj-groovy-dsl that allows to define Asciidoctor extensions in Groovy.
  
negative.code: The `extension` project is a sibling for `core`. The build file for the latter looks like this:
  
  [source,groovy]
  [subs=attributes+]
  .build.gradle
  ----
  buildscript {
  