Code review comment: I would rethink the cli/batchMode sections here (relating to the other comment, too), and push them back into the Gradle/Maven plugin to emit help appropriately (when not coming via the cli).   

Code before review:
public QuarkusCommandOutcome execute(QuarkusCommandInvocation invocation) throws QuarkusCommandException {
final MessageWriter log = invocation.log();
final boolean all = invocation.getValue(ListExtensions.ALL, true);
final boolean installedOnly = invocation.getValue(ListExtensions.INSTALLED, false);
final boolean cli = invocation.getValue(ListExtensions.FROM_CLI, false);
final String format = invocation.getValue(ListExtensions.FORMAT, "");
final String search = invocation.getValue(ListExtensions.SEARCH, "*");
final String category = invocation.getValue(ListExtensions.CATEGORY, "");
final boolean batchMode = invocation.getValue(ListExtensions.BATCH_MODE, false);
final ExtensionManager extensionManager = invocation.getValue(ListExtensions.EXTENSION_MANAGER,
invocation.getQuarkusProject().getExtensionManager());
final Collection<Extension> extensions = search == null ? invocation.getExtensionsCatalog().getExtensions()
: QuarkusCommandHandlers.select(search, invocation.getExtensionsCatalog().getExtensions(), true)
.getExtensions();
if (extensions.isEmpty()) {
log.info("No extension found with pattern '%s'", search);
return QuarkusCommandOutcome.success();
}
if (!cli) {
String extensionStatus = all ? "available" : "installable";
if (installedOnly)
extensionStatus = "installed";
log.info("%nCurrent Quarkus extensions %s: ", extensionStatus);
}
BiConsumer<MessageWriter, Object[]> currentFormatter;
switch (format.toLowerCase()) {
case "full":
currentFormatter = this::fullFormatter;
log.info(String.format(FULL_FORMAT, "Status", "Extension", "ArtifactId", "Updated Version", "Guide"));
break;
case "origins":
currentFormatter = this::originsFormatter;
break;
case "concise":
currentFormatter = this::conciseFormatter;
break;
case "name":
default:
currentFormatter = this::nameFormatter;
break;
}
Map<ArtifactKey, ArtifactCoords> installedByKey;
try {
installedByKey = extensionManager.getInstalled().stream()
.collect(toMap(ArtifactCoords::getKey, Function.identity()));
} catch (IOException e) {
throw new QuarkusCommandException("Failed to determine the list of installed extensions", e);
}
Predicate<Extension> categoryFilter;
if (StringUtils.isNotBlank(category)) {
categoryFilter = e -> ExtensionProcessor.of(e).getCategories().contains(category);
} else {
categoryFilter = e -> true;
}
extensions.stream()
.filter(e -> !ExtensionProcessor.of(e).isUnlisted())
.filter(categoryFilter)
.sorted(Comparator.comparing(e -> e.getArtifact().getArtifactId()))
.forEach(e -> display(log, e, installedByKey.get(toKey(e)), all, installedOnly, currentFormatter));
final BuildTool buildTool = invocation.getQuarkusProject().getBuildTool();
boolean isGradle = BuildTool.GRADLE.equals(buildTool) || BuildTool.GRADLE_KOTLIN_DSL.equals(buildTool);
if (!cli) {
if ("concise".equalsIgnoreCase(format) || StringUtils.isBlank(format)) {
log.info("");
if (isGradle) {
log.info(MORE_INFO_HINT, "--format=full");
} else {
log.info(MORE_INFO_HINT, "-Dformat=full");
}
}
if (!installedOnly) {
if (StringUtils.isBlank(category)) {
log.info("");
if (isGradle) {
log.info(FILTER_HINT, "--category=\"categoryId\"");
} else {
log.info(FILTER_HINT, "-Dcategory=\"categoryId\"");
}
}
}
log.info("");
if (isGradle) {
log.info(ADD_EXTENSION_HINT, "build.gradle", "./gradlew addExtension --extensions=\"artifactId\"");
} else {
log.info(ADD_EXTENSION_HINT, "pom.xml", "./mvnw quarkus:add-extension -Dextensions=\"artifactId\"");
}
} else if (!batchMode) {
if (StringUtils.isBlank(format)) {
log.info("");
log.info(MORE_INFO_HINT, "--full");
}
if (!installedOnly) {
if (StringUtils.isBlank(category)) {
log.info("");
log.info(FILTER_HINT, "--category \"categoryId\"");
}
log.info("");
if (isGradle) {
log.info(ADD_EXTENSION_HINT, "build.gradle", "quarkus extension add \"artifactId\"");
} else {
log.info(ADD_EXTENSION_HINT, "pom.xml", "quarkus extension add \"artifactId\"");
}
}
}
return QuarkusCommandOutcome.success();
}

Line under review: if ("concise".equalsIgnoreCase(format) || StringUtils.isBlank(format)) {

Code after addressing the review:
public QuarkusCommandOutcome execute(QuarkusCommandInvocation invocation) throws QuarkusCommandException {
final MessageWriter log = invocation.log();
final boolean all = invocation.getValue(ListExtensions.ALL, true);
final boolean installedOnly = invocation.getValue(ListExtensions.INSTALLED, false);
final boolean cli = invocation.getValue(ListExtensions.FROM_CLI, false);
final String format = invocation.getValue(ListExtensions.FORMAT, "");
final String search = invocation.getValue(ListExtensions.SEARCH, "*");
final String category = invocation.getValue(ListExtensions.CATEGORY, "");
final boolean batchMode = invocation.getValue(ListExtensions.BATCH_MODE, false);
final ExtensionManager extensionManager = invocation.getValue(ListExtensions.EXTENSION_MANAGER,
invocation.getQuarkusProject().getExtensionManager());
final Collection<Extension> extensions = search == null ? invocation.getExtensionsCatalog().getExtensions()
: QuarkusCommandHandlers.select(search, invocation.getExtensionsCatalog().getExtensions(), true)
.getExtensions();
if (extensions.isEmpty()) {
log.info("No extension found with pattern '%s'", search);
return QuarkusCommandOutcome.success();
}
if (!batchMode) {
String extensionStatus = all ? "available" : "installable";
if (installedOnly)
extensionStatus = "installed";
log.info("Current Quarkus extensions %s: ", extensionStatus);
log.info("");
}
BiConsumer<MessageWriter, Object[]> currentFormatter;
switch (format.toLowerCase()) {
case "full":
currentFormatter = this::fullFormatter;
log.info(String.format(FULL_FORMAT, "Status", "Extension", "ArtifactId", "Updated Version", "Guide"));
break;
case "origins":
currentFormatter = this::originsFormatter;
break;
case "concise":
currentFormatter = this::conciseFormatter;
break;
case "id":
default:
currentFormatter = this::nameFormatter;
break;
}
Map<ArtifactKey, ArtifactCoords> installedByKey;
try {
installedByKey = extensionManager.getInstalled().stream()
.collect(toMap(ArtifactCoords::getKey, Function.identity()));
} catch (IOException e) {
throw new QuarkusCommandException("Failed to determine the list of installed extensions", e);
}
Predicate<Extension> categoryFilter;
if (category != null && !category.isBlank()) {
categoryFilter = e -> ExtensionProcessor.of(e).getCategories().contains(category);
} else {
categoryFilter = e -> true;
}
extensions.stream()
.filter(e -> !ExtensionProcessor.of(e).isUnlisted())
.filter(categoryFilter)
.sorted(Comparator.comparing(e -> e.getArtifact().getArtifactId()))
.forEach(e -> display(log, e, installedByKey.get(toKey(e)), all, installedOnly, currentFormatter));
return QuarkusCommandOutcome.success();
}