diff --git a/.gitignore b/.gitignore
index d33eae53..2a351fcd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -61,3 +61,6 @@ log/
 # spc.phar
 spc.phar
 spc.exe
+
+# dumped files from StaticPHP v3
+/dump-*.json
diff --git a/src/StaticPHP/Artifact/Artifact.php b/src/StaticPHP/Artifact/Artifact.php
index dc602538..6dc35ad5 100644
--- a/src/StaticPHP/Artifact/Artifact.php
+++ b/src/StaticPHP/Artifact/Artifact.php
@@ -237,6 +237,39 @@ class Artifact
         return isset($this->config['binary'][$target]) || isset($this->custom_binary_callbacks[$target]);
     }
 
+    /**
+     * Get all platform strings for which a binary is declared (config or custom callback).
+     *
+     * For platforms where the binary type is "custom", a registered custom_binary_callback
+     * is required to consider it truly installable.
+     *
+     * @return string[] e.g. ['linux-x86_64', 'linux-aarch64', 'macos-aarch64']
+     */
+    public function getBinaryPlatforms(): array
+    {
+        $platforms = [];
+        if (isset($this->config['binary']) && is_array($this->config['binary'])) {
+            foreach ($this->config['binary'] as $platform => $platformConfig) {
+                $type = is_array($platformConfig) ? ($platformConfig['type'] ?? '') : '';
+                if ($type === 'custom') {
+                    // Only installable if a custom callback has been registered
+                    if (isset($this->custom_binary_callbacks[$platform])) {
+                        $platforms[] = $platform;
+                    }
+                } else {
+                    $platforms[] = $platform;
+                }
+            }
+        }
+        // Include custom callbacks for platforms not listed in config at all
+        foreach (array_keys($this->custom_binary_callbacks) as $platform) {
+            if (!in_array($platform, $platforms, true)) {
+                $platforms[] = $platform;
+            }
+        }
+        return $platforms;
+    }
+
     public function getDownloadConfig(string $type): mixed
     {
         return $this->config[$type] ?? null;
diff --git a/src/StaticPHP/Command/Dev/PackageInfoCommand.php b/src/StaticPHP/Command/Dev/PackageInfoCommand.php
new file mode 100644
index 00000000..7c869199
--- /dev/null
+++ b/src/StaticPHP/Command/Dev/PackageInfoCommand.php
@@ -0,0 +1,193 @@
+<?php
+
+declare(strict_types=1);
+
+namespace StaticPHP\Command\Dev;
+
+use StaticPHP\Command\BaseCommand;
+use StaticPHP\Config\ArtifactConfig;
+use StaticPHP\Config\PackageConfig;
+use StaticPHP\Registry\Registry;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Yaml\Yaml;
+
+#[AsCommand('dev:info', 'Display configuration information for a package')]
+class PackageInfoCommand extends BaseCommand
+{
+    protected bool $no_motd = true;
+
+    public function configure(): void
+    {
+        $this->addArgument('package', InputArgument::REQUIRED, 'Package name to inspect');
+        $this->addOption('json', null, InputOption::VALUE_NONE, 'Output as JSON instead of colored terminal display');
+    }
+
+    public function handle(): int
+    {
+        $packageName = $this->getArgument('package');
+
+        if (!PackageConfig::isPackageExists($packageName)) {
+            $this->output->writeln("<error>Package '{$packageName}' not found.</error>");
+            return static::USER_ERROR;
+        }
+
+        $pkgConfig = PackageConfig::get($packageName);
+        $artifactConfig = ArtifactConfig::get($packageName);
+        $pkgInfo = Registry::getPackageConfigInfo($packageName);
+        $artifactInfo = Registry::getArtifactConfigInfo($packageName);
+
+        if ($this->getOption('json')) {
+            return $this->outputJson($packageName, $pkgConfig, $artifactConfig, $pkgInfo, $artifactInfo);
+        }
+
+        return $this->outputTerminal($packageName, $pkgConfig, $artifactConfig, $pkgInfo, $artifactInfo);
+    }
+
+    private function outputJson(string $name, array $pkgConfig, ?array $artifactConfig, ?array $pkgInfo, ?array $artifactInfo): int
+    {
+        $data = [
+            'name' => $name,
+            'registry' => $pkgInfo['registry'] ?? null,
+            'package_config_file' => $pkgInfo ? $this->toRelativePath($pkgInfo['config']) : null,
+            'package' => $pkgConfig,
+        ];
+
+        if ($artifactConfig !== null) {
+            $data['artifact_config_file'] = $artifactInfo ? $this->toRelativePath($artifactInfo['config']) : null;
+            $data['artifact'] = $this->splitArtifactConfig($artifactConfig);
+        }
+
+        $this->output->writeln(json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
+        return static::SUCCESS;
+    }
+
+    private function outputTerminal(string $name, array $pkgConfig, ?array $artifactConfig, ?array $pkgInfo, ?array $artifactInfo): int
+    {
+        $type = $pkgConfig['type'] ?? 'unknown';
+        $registry = $pkgInfo['registry'] ?? 'unknown';
+        $pkgFile = $pkgInfo ? $this->toRelativePath($pkgInfo['config']) : 'unknown';
+
+        // Header
+        $this->output->writeln('');
+        $this->output->writeln("<info>Package:</info> <comment>{$name}</comment>  <info>Type:</info> <comment>{$type}</comment>  <info>Registry:</info> <comment>{$registry}</comment>");
+        $this->output->writeln("<info>Config file:</info> {$pkgFile}");
+        $this->output->writeln('');
+
+        // Package config fields (excluding type and artifact which are shown separately)
+        $pkgFields = array_diff_key($pkgConfig, array_flip(['type', 'artifact']));
+        if (!empty($pkgFields)) {
+            $this->output->writeln('<comment>── Package Config ──</comment>');
+            $this->printYamlBlock($pkgFields, 0);
+            $this->output->writeln('');
+        }
+
+        // Artifact config
+        if ($artifactConfig !== null) {
+            $artifactFile = $artifactInfo ? $this->toRelativePath($artifactInfo['config']) : 'unknown';
+            $this->output->writeln("<comment>── Artifact Config ──</comment>  <info>file:</info> {$artifactFile}");
+
+            // Check if artifact config is inline (embedded in pkg config) or separate
+            $inlineArtifact = $pkgConfig['artifact'] ?? null;
+            if (is_array($inlineArtifact)) {
+                $this->output->writeln('<info>  (inline in package config)</info>');
+            }
+
+            $split = $this->splitArtifactConfig($artifactConfig);
+
+            foreach ($split as $section => $value) {
+                $this->output->writeln('');
+                $this->output->writeln("  <info>[{$section}]</info>");
+                $this->printYamlBlock($value, 4);
+            }
+            $this->output->writeln('');
+        } else {
+            $this->output->writeln('<comment>── Artifact Config ──</comment>  <fg=gray>(none)</>');
+            $this->output->writeln('');
+        }
+
+        return static::SUCCESS;
+    }
+
+    /**
+     * Split artifact config into logical sections for cleaner display.
+     *
+     * @return array<string, mixed>
+     */
+    private function splitArtifactConfig(array $config): array
+    {
+        $sections = [];
+        $sectionOrder = ['source', 'source-mirror', 'binary', 'binary-mirror', 'metadata'];
+        foreach ($sectionOrder as $key) {
+            if (array_key_exists($key, $config)) {
+                $sections[$key] = $config[$key];
+            }
+        }
+        // Any remaining unknown keys
+        foreach ($config as $k => $v) {
+            if (!array_key_exists($k, $sections)) {
+                $sections[$k] = $v;
+            }
+        }
+        return $sections;
+    }
+
+    /**
+     * Print a value as indented YAML-style output with Symfony Console color tags.
+     */
+    private function printYamlBlock(mixed $value, int $indent): void
+    {
+        $pad = str_repeat(' ', $indent);
+        if (!is_array($value)) {
+            $this->output->writeln($pad . $this->colorScalar($value));
+            return;
+        }
+        $isList = array_is_list($value);
+        foreach ($value as $k => $v) {
+            if ($isList) {
+                if (is_array($v)) {
+                    $this->output->writeln($pad . '- ');
+                    $this->printYamlBlock($v, $indent + 2);
+                } else {
+                    $this->output->writeln($pad . '- ' . $this->colorScalar($v));
+                }
+            } else {
+                if (is_array($v)) {
+                    $this->output->writeln($pad . "<fg=cyan>{$k}</>:");
+                    $this->printYamlBlock($v, $indent + 2);
+                } else {
+                    $this->output->writeln($pad . "<fg=cyan>{$k}</>: " . $this->colorScalar($v));
+                }
+            }
+        }
+    }
+
+    private function colorScalar(mixed $v): string
+    {
+        if (is_bool($v)) {
+            return '<fg=yellow>' . ($v ? 'true' : 'false') . '</>';
+        }
+        if (is_int($v) || is_float($v)) {
+            return '<fg=yellow>' . $v . '</>';
+        }
+        if ($v === null) {
+            return '<fg=gray>null</>';
+        }
+        // Strings that look like URLs
+        if (is_string($v) && (str_starts_with($v, 'http://') || str_starts_with($v, 'https://'))) {
+            return '<fg=blue>' . $v . '</>';
+        }
+        return '<fg=green>' . $v . '</>';
+    }
+
+    private function toRelativePath(string $absolutePath): string
+    {
+        $normalized = realpath($absolutePath) ?: $absolutePath;
+        $root = rtrim(ROOT_DIR, '/') . '/';
+        if (str_starts_with($normalized, $root)) {
+            return substr($normalized, strlen($root));
+        }
+        return $normalized;
+    }
+}
diff --git a/src/StaticPHP/Package/Package.php b/src/StaticPHP/Package/Package.php
index fd59e98b..1ec1a503 100644
--- a/src/StaticPHP/Package/Package.php
+++ b/src/StaticPHP/Package/Package.php
@@ -138,6 +138,16 @@ abstract class Package
         return $this->stages;
     }
 
+    /**
+     * Get the list of OS families that have a registered build function (via #[BuildFor]).
+     *
+     * @return string[] e.g. ['Linux', 'Darwin']
+     */
+    public function getBuildForOSList(): array
+    {
+        return array_keys($this->build_functions);
+    }
+
     /**
      * Check if the package has a specific stage defined.
      *
diff --git a/src/StaticPHP/Package/PhpExtensionPackage.php b/src/StaticPHP/Package/PhpExtensionPackage.php
index 582216d7..07bc6abd 100644
--- a/src/StaticPHP/Package/PhpExtensionPackage.php
+++ b/src/StaticPHP/Package/PhpExtensionPackage.php
@@ -280,6 +280,27 @@ class PhpExtensionPackage extends Package
         $builder->deployBinary($soFile, $soFile, false);
     }
 
+    /**
+     * Get per-OS build support status for this php-extension.
+     *
+     * Rules (same as v2):
+     * - OS not listed in 'support' config  => 'yes' (fully supported)
+     * - OS listed with 'wip'               => 'wip'
+     * - OS listed with 'partial'           => 'partial'
+     * - OS listed with 'no'               => 'no'
+     *
+     * @return array<string, string> e.g. ['Linux' => 'yes', 'Darwin' => 'partial', 'Windows' => 'no']
+     */
+    public function getBuildSupportStatus(): array
+    {
+        $exceptions = $this->extension_config['support'] ?? [];
+        $result = [];
+        foreach (['Linux', 'Darwin', 'Windows'] as $os) {
+            $result[$os] = $exceptions[$os] ?? 'yes';
+        }
+        return $result;
+    }
+
     /**
      * Register default stages if not already defined by attributes.
      * This is called after all attributes have been loaded.