// KOTLIN 1.7.22
// https://mvnrepository.com/artifact/org.jetbrains.kotlin/kotlin-stdlib

https://github.com/jbangdev/jbang/blob/main/src/main/java/dev/jbang/net/KotlinManager.java
    ...
    public class KotlinManager {
	      private static final String KOTLIN_DOWNLOAD_URL = "https://github.com/JetBrains/kotlin/releases/download/v%s/kotlin-compiler-%s.zip";
	      public static final String DEFAULT_KOTLIN_VERSION = "1.6.10";
        ...
    }
    ...
https://github.com/jbangdev/jbang/blob/main/src/main/java/dev/jbang/source/sources/KotlinSource.java
    ...
    public String getKotlinVersion() {
		    return tagReader.collectOptions("KOTLIN")
						.stream()
						.findFirst()
						.orElse(KotlinManager.DEFAULT_KOTLIN_VERSION);
	  }
    ...
    protected class KotlinCompileBuildStep extends CompileBuildStep {
			public KotlinCompileBuildStep() {
				super(KotlinAppBuilder.this.project);
			}
			@Override
			protected String getCompilerBinary(String requestedJavaVersion) {
				return resolveInKotlinHome("kotlinc", ((KotlinSource) project.getMainSource()).getKotlinVersion());
			}
		}
    ...

src/main/java/dev/jbang/source/Source.java
https://github.com/jbangdev/jbang/blob/main/src/main/java/dev/jbang/source/Source.java
    public abstract class Source {

      private final ResourceRef resourceRef;
      private final String contents;
      protected final TagReader tagReader;

      public enum Type {
        java("java"), jshell("jsh"), kotlin("kt"),
        groovy("groovy"), markdown("md");

        public final String extension;

        Type(String extension) {
          this.extension = extension;
        }

        public static List<String> extensions() {
          return Arrays.stream(values()).map(v -> v.extension).collect(Collectors.toList());
        }
      }

      public Source(String contents, Function<String, String> replaceProperties) {
        this(ResourceRef.nullRef, contents, replaceProperties);
      }

      protected Source(ResourceRef resourceRef, Function<String, String> replaceProperties) {
        this(resourceRef, Util.readFileContent(resourceRef.getFile()), replaceProperties);
      }

      protected Source(ResourceRef resourceRef, String contents, Function<String, String> replaceProperties) {
        this.resourceRef = resourceRef;
        this.contents = contents;
        this.tagReader = createTagReader(contents, replaceProperties);
      }

      protected TagReader createTagReader(String contents, Function<String, String> replaceProperties) {
        return new TagReader.Extended(contents, replaceProperties);
      }
      ...
    }

src/main/java/dev/jbang/source/TagReader.java
public abstract class TagReader {
	protected final String contents;
	protected final Function<String, String> replaceProperties;

	// Cached values
	private List<String> lines;

	private static final String REPOS_COMMENT_PREFIX = "REPOS ";
	private static final String DEPS_COMMENT_PREFIX = "DEPS ";
	private static final String FILES_COMMENT_PREFIX = "FILES ";
	private static final String SOURCES_COMMENT_PREFIX = "SOURCES ";
	private static final String DESCRIPTION_COMMENT_PREFIX = "DESCRIPTION ";
	private static final String GAV_COMMENT_PREFIX = "GAV ";

	private static final Pattern EOL = Pattern.compile("\\r?\\n");

	public TagReader(String contents, Function<String, String> replaceProperties) {
		this.contents = contents;
		this.replaceProperties = replaceProperties != null ? replaceProperties : Function.identity();
	}

  protected String getContents() {
		return contents;
	}

	protected abstract Stream<String> getTags();

  ...
	@Nonnull
	public List<String> collectOptions(String... prefixes) {
		List<String> options;
		if (prefixes.length > 1) {
			options = new ArrayList<>();
			for (String prefix : prefixes) {
				options.addAll(collectRawOptions(prefix));
			}
		} else {
			options = collectRawOptions(prefixes[0]);
		}

		// convert quoted content to list of strings as
		// just passing "--enable-preview --source 14" fails
		return Project.quotedStringToList(String.join(" ", options));
	}

  @Nonnull
	List<String> collectRawOptions(String prefix) {
		List<String> javaOptions = getTags()
											.map(it -> it.split(" // ")[0]) // strip away nested comments.
											.filter(it -> it.startsWith(prefix + " ")
													|| it.startsWith(prefix + "\t") || it.equals(prefix))
											.map(it -> it.replaceFirst(prefix, "").trim())
											.collect(Collectors.toList());

		String envOptions = System.getenv("JBANG_" + prefix);
		if (envOptions != null) {
			javaOptions.add(envOptions);
		}
		return javaOptions;
	}
  ...
	/**
	 * This class extends the default <code>TagReader</code> with support for Groovy
	 * "grab" annotations.
	 */
	public static class Extended extends TagReader {
		private static final String DEPS_ANNOT_PREFIX = "@Grab(";
		private static final Pattern DEPS_ANNOT_PAIRS = Pattern.compile("(?<key>\\w+)\\s*=\\s*\"(?<value>.*?)\"");
		private static final Pattern DEPS_ANNOT_SINGLE = Pattern.compile("@Grab\\(\\s*\"(?<value>.*)\"\\s*\\)");

		private static final String REPOS_ANNOT_PREFIX = "@GrabResolver(";
		private static final Pattern REPOS_ANNOT_PAIRS = Pattern.compile("(?<key>\\w+)\\s*=\\s*\"(?<value>.*?)\"");
		private static final Pattern REPOS_ANNOT_SINGLE = Pattern.compile(
				"@GrabResolver\\(\\s*\"(?<value>.*)\"\\s*\\)");

		public Extended(String contents, Function<String, String> replaceProperties) {
			super(contents, replaceProperties);
		}

		@Override
		protected Stream<String> getTags() {
			return EOL	.splitAsStream(contents)
						.filter(s -> s.startsWith("//")
								|| s.contains(DEPS_ANNOT_PREFIX)
								|| s.contains(REPOS_ANNOT_PREFIX))
						.map(s -> s.contains(DEPS_ANNOT_PREFIX)
								|| s.contains(REPOS_ANNOT_PREFIX) ? s : s.substring(2));
		}
    ...
  }
  ...