Add note that DOTNET_ADDITIONAL_DEPS only works with framework-dependent applications (#36038)

* Initial plan

* Add note that DOTNET_ADDITIONAL_DEPS only works with framework-dependent apps

Co-authored-by: tdykstra <[email protected]>

* Update aspnetcore/fundamentals/host/platform-specific-configuration.md

Co-authored-by: Wade Pickett <[email protected]>

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: tdykstra <[email protected]>
Co-authored-by: Tom Dykstra <[email protected]>
Co-authored-by: Wade Pickett <[email protected]>

Author: 3 people

aspnetcore/fundamentals/host/platform-specific-configuration.md

@@ -5,7 +5,7 @@ description: Discover how to enhance an ASP.NET Core app from an external assemb
 monikerRange: '>= aspnetcore-2.1'
 ms.author: tdykstra
 ms.custom: mvc
-ms.date: 09/26/2019
+ms.date: 09/04/2025
 uid: fundamentals/configuration/platform-specific-configuration
 ---
 # Use hosting startup assemblies in ASP.NET Core
@@ -336,6 +336,9 @@ deployment/additionalDeps/shared/Microsoft.AspNetCore.App/3.0.0/StartupDiagnosti
 
 For runtime to discover the runtime store location, the additional dependencies file location is added to the `DOTNET_ADDITIONAL_DEPS` environment variable.
 
+> [!NOTE]
+> The `DOTNET_ADDITIONAL_DEPS` environment variable only works with framework-dependent applications. This environment variable is ignored for self-contained applications.
+
 In the sample app (*RuntimeStore* project), building the runtime store and generating the additional dependencies file is accomplished using a [PowerShell](/powershell/scripting/overview) script.
 
 For examples of how to set environment variables for various operating systems, see [Use multiple environments](xref:fundamentals/environments).
@@ -722,6 +725,9 @@ deployment/additionalDeps/shared/Microsoft.AspNetCore.App/2.1.0/StartupDiagnosti
 
 For runtime to discover the runtime store location, the additional dependencies file location is added to the `DOTNET_ADDITIONAL_DEPS` environment variable.
 
+> [!NOTE]
+> The `DOTNET_ADDITIONAL_DEPS` environment variable only works with framework-dependent applications. This environment variable is ignored for self-contained applications.
+
 In the sample app (*RuntimeStore* project), building the runtime store and generating the additional dependencies file is accomplished using a [PowerShell](/powershell/scripting/overview) script.
 
 For examples of how to set environment variables for various operating systems, see [Use multiple environments](xref:fundamentals/environments).