Some targets still target v8.0 (api26):
src/KeePassLib2Android/KeePassLib2Android.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/KP2AKdbLibraryBinding/KP2AKdbLibraryBinding.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/ZlibAndroid/ZlibAndroid.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/PluginSdkBinding/PluginSdkBinding.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/PCloudBindings/PCloudBindings.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/AndroidFileChooserBinding/AndroidFileChooserBinding.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
src/TwofishCipher/TwofishCipher.csproj: <TargetFrameworkVersion>v8.0</TargetFrameworkVersion>
So we need it in ANDROID_SDK_ROOT.
Otherwise build fails with this error (on macos & windows):
C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Xamarin\Android\Xamarin.Android.Tooling.targets(100,5): error XA5207: Could not find android.jar for API level 26. This means the Android SDK platform for API level 26 is not installed. Either install it in the Android SDK Manager (Tools > Android > Android SDK Manager...), or change the Xamarin.Android project to target an API version that is installed. (C:\Android\android-sdk\platforms\android-26\android.jar missing.) [D:\a\keepass2android\keepass2android\src\TwofishCipher\TwofishCipher.csproj]