Add remarks regarding architecture emulation

Co-authored-by: Jan Kotas <jkotas@microsoft.com>

Author: AaronRobinsonMSFT

xml/System.Runtime.InteropServices/RuntimeInformation.xml

@@ -81,17 +81,17 @@
  <summary>Gets the name of the .NET installation on which an app is running.</summary>
  <value>The name of the .NET installation on which the app is running.</value>
  <remarks>
- <format type="text/markdown"><![CDATA[ 
- 
+ <format type="text/markdown"><![CDATA[
+
 ## Remarks
 
-The property returns a string that indicates the name of the currently executing .NET implementation. The string starts with one of the following descriptions, usually followed by the current version: 
+The property returns a string that indicates the name of the currently executing .NET implementation. The string starts with one of the following descriptions, usually followed by the current version:
 
 - ".NET" (for .NET 5 and later versions)
 - ".NET Core" (for .NET Core 1.0 - 3.1)
 - ".NET Framework"
 - ".NET Native"
- 
+
  ]]></format>
  </remarks>
  </Docs>
@@ -184,7 +184,15 @@ The property returns a string that indicates the name of the currently executing
  <Docs>
  <summary>Gets the platform architecture on which the current app is running.</summary>
  <value>The platform architecture on which the current app is running.</value>
- <remarks>To be added.</remarks>
+ <remarks>
+ <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+The returned value is intended to represent the actual architecture of the underlying operating system. It is a best effort to ignore the architecture emulation infrastructure that may be involved to run the process. The returned value takes into account emulation built into Windows and macOS operating systems. The returned value does not take into account emulation using QEMU that is typically used on Linux operating system. 
+
+ ]]></format>
+ </remarks>
  </Docs>
  </Member>
  <Member MemberName="OSDescription">
@@ -313,7 +321,7 @@ The property returns a string that indicates the name of the currently executing
 This property returns a string that identifies the operating system, typically including the version and processor architecture of the currently executing process.
 
 Since this string is opaque, it's not recommended to parse the string into its constituent parts.
- 
+
 For more information, see [.NET Core RID catalog](/dotnet/core/rid-catalog).
 
  ]]></format>