diff --git a/README.md b/README.md
index ecc0b1d..7a57030 100644
--- a/README.md
+++ b/README.md
@@ -99,9 +99,12 @@ for _, f := range result.Files {
 
 ## Supported formats
 
-- `.zip`, `.jar`, `.whl`, `.nupkg`, `.egg` (ZIP-based)
-- `.tar`, `.tar.gz`, `.tgz`, `.tar.bz2`, `.tar.xz`
+- `.zip`, `.jar`, `.whl`, `.nupkg`, `.egg`, `.vsix` (ZIP-based)
+- `.tar`, `.tar.gz`, `.tgz`, `.crate`, `.tar.bz2`, `.tar.xz`
 - `.gem` (Ruby gems with nested data.tar.gz)
+- `.apk` (routed by content: Android packages open as ZIP, Alpine packages open as gzipped tar)
+
+Filenames without a recognised extension are opened by inspecting the first bytes for a ZIP, tar, gzip, bzip2, or xz signature.
 
 ## License
 
diff --git a/archives.go b/archives.go
index 6b10360..a2bc1a3 100644
--- a/archives.go
+++ b/archives.go
@@ -1,10 +1,14 @@
 // Package archives provides in-memory archive reading and browsing capabilities.
 //
 // It supports multiple archive formats including:
-//   - ZIP (.zip, .jar, .whl, .nupkg)
-//   - TAR (.tar, .tar.gz, .tgz, .tar.bz2, .tar.xz)
+//   - ZIP (.zip, .jar, .whl, .nupkg, .egg, .vsix)
+//   - TAR (.tar, .tar.gz, .tgz, .crate, .tar.bz2, .tar.xz)
 //   - GEM (.gem - Ruby gems with nested tar structure)
 //
+// The .apk extension is routed by content since Android packages are ZIP
+// and Alpine packages are gzipped tar. Filenames without a recognised
+// extension are opened by inspecting the first bytes.
+//
 // The package is designed to work entirely in memory without writing to disk,
 // making it suitable for browsing cached artifacts on-demand.
 package archives
@@ -205,14 +209,16 @@ func detectFormat(filename string) string {
 		return formatTarXZ
 	}
 
-	// Check simple extensions
+	// Check simple extensions. .apk is deliberately absent: Alpine packages
+	// are gzipped tarballs and Android packages are zips, so it falls
+	// through to content sniffing.
 	ext := path.Ext(filename)
 	switch ext {
-	case ".zip", ".jar", ".whl", ".nupkg", ".egg":
+	case ".zip", ".jar", ".whl", ".nupkg", ".egg", ".vsix":
 		return formatZIP
 	case ".tar":
 		return formatTAR
-	case ".tgz":
+	case ".tgz", ".crate":
 		return formatTGZ
 	case ".gem":
 		return formatGem
diff --git a/archives_test.go b/archives_test.go
index c343c57..780acc6 100644
--- a/archives_test.go
+++ b/archives_test.go
@@ -32,6 +32,9 @@ func TestDetectFormat(t *testing.T) {
 		{"package.tar.bz2", "tar.bz2"},
 		{"package.tar.xz", "tar.xz"},
 		{"package.gem", "gem"},
+		{"package.vsix", "zip"},
+		{"package.crate", "tgz"},
+		{"package.apk", ""}, // Ambiguous: routed by content sniff
 		{"unknown.txt", ""},
 		{"Package.ZIP", "zip"}, // Case insensitive
 		{"package.TAR.GZ", "tar.gz"},
@@ -357,6 +360,50 @@ func TestOpenDetectsExtensionlessArchives(t *testing.T) {
 	}
 }
 
+func TestOpenRegistryArtifactExtensions(t *testing.T) {
+	tests := []struct {
+		filename string
+		data     []byte
+		want     string
+	}{
+		{"serde-1.0.0.crate", createTestTarGz(), "*archives.tarReader"},
+		{"extension-1.0.0.vsix", createTestZip(), "*archives.zipReader"},
+		{"android.apk", createTestZip(), "*archives.zipReader"},
+		{"alpine.apk", createTestTarGz(), "*archives.tarReader"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.filename+"/Open", func(t *testing.T) {
+			reader, err := Open(test.filename, bytes.NewReader(test.data))
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer func() { _ = reader.Close() }()
+			if got := fmt.Sprintf("%T", reader); got != test.want {
+				t.Fatalf("reader = %s, want %s", got, test.want)
+			}
+			files, err := reader.List()
+			if err != nil {
+				t.Fatal(err)
+			}
+			if len(files) == 0 {
+				t.Fatal("archive contains no files")
+			}
+		})
+
+		t.Run(test.filename+"/OpenBytes", func(t *testing.T) {
+			reader, err := OpenBytes(test.filename, test.data)
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer func() { _ = reader.Close() }()
+			if got := fmt.Sprintf("%T", reader); got != test.want {
+				t.Fatalf("reader = %s, want %s", got, test.want)
+			}
+		})
+	}
+}
+
 func TestOpenLimitsUnsupportedContentRead(t *testing.T) {
 	content := bytes.NewReader(bytes.Repeat([]byte("x"), contentSniffSize*4))
 	_, err := Open("artifact", content)