Document Package Source Mapping error NU1110 (#3169)

Author: donnie-msft

docs/TOC.md

@@ -162,6 +162,7 @@
 ### [NU1107](reference/errors-and-warnings/NU1107.md)
 ### [NU1108](reference/errors-and-warnings/NU1108.md)
 ### [NU1109](reference/errors-and-warnings/NU1109.md)
+### [NU1110](reference/errors-and-warnings/NU1110.md)
 ### [NU1201](reference/errors-and-warnings/NU1201.md)
 ### [NU1202](reference/errors-and-warnings/NU1202.md)
 ### [NU1203](reference/errors-and-warnings/NU1203.md)

docs/reference/Errors-and-Warnings.md

@@ -29,6 +29,7 @@ NuGet supports the following configuration properties.
 | --- | --- |
 | Invalid input errors | [NU1001](./errors-and-warnings/NU1001.md), [NU1002](./errors-and-warnings/NU1002.md), [NU1003](./errors-and-warnings/NU1003.md), [NU1004](./errors-and-warnings/NU1004.md), [NU1005](./errors-and-warnings/NU1005.md), [NU1006](./errors-and-warnings/NU1006.md), [NU1007](./errors-and-warnings/NU1007.md), [NU1008](./errors-and-warnings/NU1008.md), [NU1009](./errors-and-warnings/NU1009.md), [NU1010](./errors-and-warnings/NU1010.md), [NU1011](./errors-and-warnings/NU1011.md), [NU1012](./errors-and-warnings/NU1012.md), |
 | Missing package and project errors | [NU1100](./errors-and-warnings/NU1100.md), [NU1101](./errors-and-warnings/NU1101.md), [NU1102](./errors-and-warnings/NU1102.md), [NU1103](./errors-and-warnings/NU1103.md), [NU1104](./errors-and-warnings/NU1104.md), [NU1105](./errors-and-warnings/NU1105.md), [NU1106](./errors-and-warnings/NU1106.md), [NU1107](./errors-and-warnings/NU1107.md), [NU1108](./errors-and-warnings/NU1108.md), [NU1109](./errors-and-warnings/NU1109.md) |
+| Package source mapping errors | [NU1110](./errors-and-warnings/NU1110.md)
 | Compatibility errors | [NU1201](./errors-and-warnings/NU1201.md), [NU1202](./errors-and-warnings/NU1202.md), [NU1203](./errors-and-warnings/NU1203.md), [NU1204](./errors-and-warnings/NU1204.md), [NU1401](./errors-and-warnings/NU1401.md), [NU1402](./errors-and-warnings/NU1402.md), [NU1403](./errors-and-warnings/NU1403.md) |
 | Dotnet Tool restore errors | [NU1211](./errors-and-warnings/NU1211.md), [NU1212](./errors-and-warnings/NU1212.md), [NU1213](./errors-and-warnings/NU1213.md) |
 | NuGet source errors | [NU1301](./errors-and-warnings/NU1301.md) |

docs/reference/errors-and-warnings/NU1110.md

@@ -0,0 +1,36 @@
+---
+title: NuGet Error NU1110
+description: NU1110 error code
+author: donnie-msft
+ms.author: eagoodso
+ms.date: 10/27/2023
+ms.topic: reference
+f1_keywords: 
+  - "NU1110"
+---
+
+# NuGet Error NU1110
+
+<pre>NU1110: The package `B` is available in the Global packages folder, but the source it came from `https://api.nuget.org/v3/index.json` is not one of the configured sources.
+</pre>
+
+### Issue
+
+A previous restore retrieved package `B` from a package source which your current solution does not have configured.
+
+While performing a package installation of package `A`, a dependent package `B` was needed transitively to complete the action. Restore found `B` in your [Global packages folder](../../consume-packages/managing-the-global-packages-and-cache-folders.md)), and the accompanying `nupkg.metadata` indicates a `Source` value which it cannot find in your solution.
+
+When [package source mapping](../../consume-packages/Package-Source-Mapping.md) is enabled, NuGet attempts to map transitive dependencies automatically by analyzing the source in the Global packages folder.
+
+### Solution
+
+#### Option 1. 
+Create a package source mapping for package `B`.
+
+#### Option 2.
+Clear package `B` from your Global packages folder so that restore can download from one of your configured packages sources. For more information, see [Managing the global packages, cache, and temp folders](../../consume-packages/managing-the-global-packages-and-cache-folders.md).
+
+If your other solutions have different package sources and package source mapping configurations, this option may not be feasible.
+
+#### Option 3.
+Consider enabling a package source which you know has package `B` available.