@@ -13,6 +13,7 @@ public partial class ReClassNetFile
 		private const string SerialisationClassName = "__Serialization_Class__";
 
 		public const string XmlRootElement = "reclass";
+		public const string XmlCustomDataElement = "custom_data";
 		public const string XmlClassesElement = "classes";
 		public const string XmlClassElement = "class";
 		public const string XmlNodeElement = "node";
 
@@ -49,6 +49,15 @@ public void Load(Stream input, ILogger logger)
 						logger.Log(LogLevel.Warning, $"The platform of the file ({platform}) doesn't match the program platform ({Constants.Platform}).");
 					}
 
+					var customDataElement = document.Root.Element(XmlCustomDataElement);
+					if (customDataElement != null)
+					{
+						foreach (var kv in customDataElement.Elements())
+						{
+							project.CustomData[kv.Name.ToString()] = kv.Value;
+						}
+					}
+
 					var classes = new List<Tuple<XElement, ClassNode>>();
 
 					foreach (var element in document.Root
 
@@ -33,7 +33,8 @@ public void Save(Stream output, ILogger logger)
 							XmlRootElement,
 							new XAttribute(XmlVersionAttribute, Version1),
 							new XAttribute(XmlPlatformAttribute, Constants.Platform),
-							new XElement(XmlClassesElement, CreateClassElements(project.Classes, logger))
+							new XElement(XmlClassesElement, CreateClassElements(project.Classes, logger)),
+							new XElement(XmlCustomDataElement, project.CustomData.Select(kv => new XElement(kv.Key, kv.Value)))
 						)
 					);
 
 
@@ -19,6 +19,12 @@ public class ReClassNetProject : IDisposable
 
 		public string Path { get; set; }
 
+		/// <summary>
+		/// Key-Value map with custom data for plugins to store project related data.
+		/// The preferred key format is {Plugin Name}_{Key Name}.
+		/// </summary>
+		public Dictionary<string, string> CustomData { get; } = new Dictionary<string, string>();
+
 		public void Dispose()
 		{
 			Clear();
Original file line number	Diff line number	Diff line change
`@@ -33,7 +33,8 @@ public void Save(Stream output, ILogger logger)`
`33`	`33`	`XmlRootElement,`
`34`	`34`	`new XAttribute(XmlVersionAttribute, Version1),`
`35`	`35`	`new XAttribute(XmlPlatformAttribute, Constants.Platform),`
`36`		`- new XElement(XmlClassesElement, CreateClassElements(project.Classes, logger))`
	`36`	`+ new XElement(XmlClassesElement, CreateClassElements(project.Classes, logger)),`
	`37`	`+ new XElement(XmlCustomDataElement, project.CustomData.Select(kv => new XElement(kv.Key, kv.Value)))`
`37`	`38`	`)`
`38`	`39`	`);`
`39`	`40`