Soo.... Android, yes.

After a few months of names like `arc.so.bin` or `#Assembly.dll.so` or
`assemblies.arm64-v8a.blob.so` working just fine, Android 14 (on Pixel
6) stopped extracting entries with such names to the filesystem when the
`extractNativeLibs` flag is set to `true` in the manifest.  Not only
"special" characters (tested `#`, `!`, `~`, `@`, `%` and then gave up)
are no longer accepted - `lib/{ARCH]` entries with them are ignored and
not extracted to the file system, but also any entries without the `lib`
prefix are ignored (but ONLY on Release builds).

So, the new mangling style is:

  * `lib_` prefix for regular assemblies
  * `lib-culture-` prefix for satellite assemblies.

Also, all the entries we place in `lib` are now compressed, as per the
build mode.

Let's see which tests break now.

src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs

@@ -421,8 +421,8 @@ void AddAssemblies (ZipArchiveEx apk, bool debug, bool compress, IDictionary<And
 				foreach (string abi in SupportedAbis) {
 					// Prefix it with `a` because bundletool sorts entries alphabetically, and this will place it right next to `assemblies.*.blob.so`, which is what we
 					// like since we can finish scanning the zip central directory earlier at startup.
-					inArchivePath = MakeArchiveLibPath (abi, "arc.bin.so");
-					AddFileToArchiveIfNewer (apk, RuntimeConfigBinFilePath, inArchivePath, compressionMethod: UncompressedMethod);
+					inArchivePath = MakeArchiveLibPath (abi, "libarc.bin.so");
+					AddFileToArchiveIfNewer (apk, RuntimeConfigBinFilePath, inArchivePath, compressionMethod: GetCompressionMethod (inArchivePath));
 				}
 			}
 
@@ -442,8 +442,8 @@ void AddAssemblies (ZipArchiveEx apk, bool debug, bool compress, IDictionary<And
 
 			foreach (var kvp in assemblyStorePaths) {
 				string abi = MonoAndroidHelper.ArchToAbi (kvp.Key);
-				inArchivePath = MakeArchiveLibPath (abi, Path.GetFileName (kvp.Value));
-				AddFileToArchiveIfNewer (apk, kvp.Value, inArchivePath, UncompressedMethod);
+				inArchivePath = MakeArchiveLibPath (abi, "lib" + Path.GetFileName (kvp.Value));
+				AddFileToArchiveIfNewer (apk, kvp.Value, inArchivePath, GetCompressionMethod (inArchivePath));
 			}
 
 			void AddAssembliesFromCollection (ITaskItem[] assemblies)
@@ -649,14 +649,14 @@ void AddAssemblyConfigEntry (ZipArchiveEx apk, string assemblyPath, string confi
 				// All of the assemblies have their names mangled so that the possibility to clash with "real" shared
 				// library names is minimized. All of the assembly entries will start with a special character:
 				//
-				//   # - for regular assemblies (e.g. `#Mono.Android.dll.so`)
-				//   % - for satellite assemblies (e.g. `%es%Mono.Android.dll.so`)
+				//   `_` - for regular assemblies (e.g. `_Mono.Android.dll.so`)
+				//   `-` - for satellite assemblies (e.g. `-es-Mono.Android.dll.so`)
 				//
 				// Second of all, we need to treat satellite assemblies with even more care.
 				// If we encounter one of them, we will return the culture as part of the path transformed
-				// so that it forms a `%culture%` assembly file name prefix, not a `culture/` subdirectory.
+				// so that it forms a `-culture-` assembly file name prefix, not a `culture/` subdirectory.
 				// This is necessary because Android doesn't allow subdirectories in `lib/{ABI}/`
-
+				//
 				string[] subdirParts = subDirectory.TrimEnd ('/').Split ('/');
 				if (subdirParts.Length == 1) {
 					// Not a satellite assembly

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/PackagingTest.cs

@@ -80,7 +80,7 @@ public void CheckIncludedAssemblies ([Values (false, true)] bool usesAssemblySto
 				"System.Collections.dll",
 				"System.Collections.Concurrent.dll",
 				"System.Text.RegularExpressions.dll",
-				"arc.bin.so",
+				"libarc.bin.so",
 			};
 
 			using (var b = CreateApkBuilder ()) {

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/ArchiveAssemblyHelper.cs

@@ -250,11 +250,16 @@ public int GetNumberOfAssemblies (bool forceRefresh = false, AndroidTargetArch a
 		{
 			List<string> contents = ListArchiveContents (assembliesRootDir, forceRefresh, arch);
 
-			// We must count only .dll.so entries starting with the '#' character, as they are the actual managed assemblies.
+			// We must count only .dll.so entries starting with the '-' and '_' characters, as they are the actual managed assemblies.
 			// Other entries in `lib/{arch}` might be AOT shared libraries, which will also have the .dll.so extension.
 			var dlls = contents.Where (x => {
 				string fileName = Path.GetFileName (x);
-				return fileName[0] == '#' && fileName.EndsWith (".dll.so", StringComparison.OrdinalIgnoreCase);
+				if (!fileName.EndsWith (".dll.so", StringComparison.OrdinalIgnoreCase)) {
+					return false;
+				}
+
+				return fileName.StartsWith (MonoAndroidHelper.MANGLED_ASSEMBLY_REGULAR_ASSEMBLY_MARKER, StringComparison.OrdinalIgnoreCase) ||
+				       fileName.StartsWith (MonoAndroidHelper.MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER, StringComparison.OrdinalIgnoreCase);
 			});
 
 			return dlls.Count ();
@@ -319,7 +324,7 @@ public int GetNumberOfAssemblies (bool forceRefresh = false, AndroidTargetArch a
 					break;
 			}
 
-			char fileTypeMarker = '#';
+			string fileTypeMarker = MonoAndroidHelper.MANGLED_ASSEMBLY_REGULAR_ASSEMBLY_MARKER;
 			var abis = new List<string> ();
 			if (!String.IsNullOrEmpty (abi)) {
 				abis.Add (abi);
@@ -334,8 +339,8 @@ public int GetNumberOfAssemblies (bool forceRefresh = false, AndroidTargetArch a
 			if (!String.IsNullOrEmpty (culture)) {
 				// Android doesn't allow us to put satellite assemblies in lib/{CULTURE}/assembly.dll.so, we must instead
 				// mangle the name.
-				fileName = $"{culture}%{fileName}";
-				fileTypeMarker = '%';
+				fileTypeMarker = MonoAndroidHelper.MANGLED_ASSEMBLY_SATELLITE_ASSEMBLY_MARKER;
+				fileName = $"{culture}{fileTypeMarker}-{fileName}";
 			}
 
 			var ret = new List<string> ();
@@ -479,23 +484,6 @@ IEnumerable<string> GetAdditionalFilesForAbi (string abi, List<string> existingF
 				(string prefixAssemblies, string prefixLib) = GetArchivePrefixes (abi);
 				return existingFiles.Where (x => !fileNames.Contains (x.Replace (prefixAssemblies, string.Empty)) && !fileNames.Contains (x.Replace (prefixLib, String.Empty)));
 			}
-
-			string GetUnmangledFileName (string fullName)
-			{
-				string fileName = Path.GetFileName (fullName);
-				switch(fileName[0]) {
-					case '#':
-						// Drop the '#' prefix and the .so extension
-						return Path.GetFileNameWithoutExtension (fileName.Substring (1));
-
-					case '%':
-						// Drop the '%' prefix, replace the following '%s' with `/` to get a culture/Assembly file name and drop the .so extension
-						return Path.GetFileNameWithoutExtension (fileName.Substring (1).Replace ('%', '/'));
-
-					default:
-						return fileName;
-				}
-			}
 		}
 
 		void StoreContains (ICollection<string> fileNames, out List<string> existingFiles, out List<string> missingFiles, out List<string> additionalFiles, IEnumerable<AndroidTargetArch>? targetArches = null)

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Resources/Base/BuildReleaseArm64SimpleDotNet.apkdesc

@@ -7,37 +7,37 @@
     "classes.dex": {
       "Size": 377856
     },
-    "lib/arm64-v8a/#_Microsoft.Android.Resource.Designer.dll.so": {
+    "lib/arm64-v8a/lib__Microsoft.Android.Resource.Designer.dll.so": {
       "Size": 1027
     },
-    "lib/arm64-v8a/#Java.Interop.dll.so": {
+    "lib/arm64-v8a/lib_Java.Interop.dll.so": {
       "Size": 61443
     },
-    "lib/arm64-v8a/#Mono.Android.dll.so": {
+    "lib/arm64-v8a/lib_Mono.Android.dll.so": {
       "Size": 90421
     },
-    "lib/arm64-v8a/#Mono.Android.Runtime.dll.so": {
+    "lib/arm64-v8a/lib_Mono.Android.Runtime.dll.so": {
       "Size": 5143
     },
-    "lib/arm64-v8a/#System.Console.dll.so": {
+    "lib/arm64-v8a/lib_System.Console.dll.so": {
       "Size": 6537
     },
-    "lib/arm64-v8a/#System.Linq.dll.so": {
+    "lib/arm64-v8a/lib_System.Linq.dll.so": {
       "Size": 8540
     },
-    "lib/arm64-v8a/#System.Private.CoreLib.dll.so": {
+    "lib/arm64-v8a/lib_System.Private.CoreLib.dll.so": {
       "Size": 552396
     },
-    "lib/arm64-v8a/#System.Runtime.dll.so": {
+    "lib/arm64-v8a/lib_System.Runtime.dll.so": {
       "Size": 2541
     },
-    "lib/arm64-v8a/#System.Runtime.InteropServices.dll.so": {
+    "lib/arm64-v8a/lib_System.Runtime.InteropServices.dll.so": {
       "Size": 4019
     },
-    "lib/arm64-v8a/#UnnamedProject.dll.so": {
+    "lib/arm64-v8a/lib_UnnamedProject.dll.so": {
       "Size": 2931
     },
-    "lib/arm64-v8a/arc.bin.so": {
+    "lib/arm64-v8a/libarc.bin.so": {
       "Size": 1512
     },
     "lib/arm64-v8a/libmono-component-marshal-ilgen.so": {