In the past you could tell the nodes in a test cluster to attach themselves to a waiting debugger on startup by passing the `--debug-server-jvm` option documented here:

https://github.com/elastic/elasticsearch/blob/c0228c73fea5caf279bf7141eabea50813c4528b/TESTING.asciidoc#L383-L390

I think this changed in #92379 and no longer seems to work. In fact I really wanted to attach a debugger to just one of the nodes in the cluster, and I believe #92379 might make this much easier to use (e.g. maybe via a method `LocalNodeSpecBuilder#debuggerPort(int)`). That'd be even better.
test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterFactory.java
finalSettings.put("path.logs", logsDir.toString());
                finalSettings.putAll(spec.resolveSettings());
                Files.writeString(
                    configFile,
                    finalSettings.entrySet()
                        .stream()
                        .map(entry -> entry.getKey() + ": " + entry.getValue())
                        .collect(Collectors.joining("\n")),
                    StandardOpenOption.TRUNCATE_EXISTING,
                    StandardOpenOption.CREATE
                );
                
                try (Stream<Path> configFiles = Files.list(distributionDir.resolve("config"))) {
                    for (Path file : configFiles.toList()) {
                        Path dest = configFile.getParent().resolve(file.getFileName());
                        if (Files.exists(dest) == false) {
                            Files.copy(file, dest);
                        }
                    }
                }
                
                String content = Files.readString(jvmOptionsFile);
                Map<String, String> expansions = getJvmOptionsReplacements();
                for (String key : expansions.keySet()) {
                    if (content.contains(key) == false) {
                        throw new IOException("Template property '" + key + "' not found in template.");
                    }
                    content = content.replace(key, expansions.get(key));
                }
                Files.writeString(jvmOptionsFile, content);