Default location of .NET on Linux varies (#34834)

Author: tdykstra

docs/core/tools/dotnet-environment-variables.md

@@ -1,7 +1,7 @@
 ---
 title: .NET environment variables
 description: Learn about the environment variables that you can use to configure the .NET SDK, .NET CLI, and .NET runtime.
-ms.date: 09/07/2022
+ms.date: 03/30/2023
 ---
 
 # .NET environment variables
@@ -181,7 +181,13 @@ See [EventPipe environment variables](../diagnostics/eventpipe.md#trace-using-en
 
 ### `DOTNET_ROOT`, `DOTNET_ROOT(x86)`
 
-Specifies the location of the .NET runtimes, if they are not installed in the default location. The default location on Windows is `C:\Program Files\dotnet`. The default location on Linux and macOS is `/usr/local/share/dotnet`. This environment variable is used only when running apps via generated executables (apphosts). `DOTNET_ROOT(x86)` is used instead when running a 32-bit executable on a 64-bit OS.
+Specifies the location of the .NET runtimes, if they are not installed in the default location. The default location on Windows is `C:\Program Files\dotnet`. The default location on macOS is `/usr/local/share/dotnet`. The default location on Linux varies depending on distro and installment method. The default location on Ubuntu 22.04 is `/usr/share/dotnet` (when installed from `packages.microsoft.com`) or `/usr/lib/dotnet` (when installed from Jammy feed). For more information, see the following resources:
+
+* [Troubleshoot app launch failures](../runtime-discovery/troubleshoot-app-launch.md?pivots=os-linux)
+* GitHub issue [dotnet/core#7699](https://github.com/dotnet/core/issues/7699)
+* GitHub issue [dotnet/runtime#79237](https://github.com/dotnet/runtime/issues/79237)
+
+This environment variable is used only when running apps via generated executables (apphosts). `DOTNET_ROOT(x86)` is used instead when running a 32-bit executable on a 64-bit OS.
 
 ### `NUGET_PACKAGES`