Introduced a very simple "singleton" service-locator, which allowed for a removal of specific implementations which were very limited. With this it's easier to access dependencies.

GreenshotPlugin/Interfaces/Plugin/PluginAttribute.cs

@@ -0,0 +1,51 @@
+/*
+ * Greenshot - a free and open source screenshot tool
+ * Copyright (C) 2007-2020 Thomas Braun, Jens Klingen, Robin Krom
+ * 
+ * For more information see: http://getgreenshot.org/
+ * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 1 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+
+namespace Greenshot.Plugin {
+	[Serializable]
+	[AttributeUsage(AttributeTargets.Class, Inherited = false, AllowMultiple = false)]
+	public sealed class PluginAttribute : Attribute, IComparable {
+		public string Name {
+			get;
+			set;
+		}
+
+        public bool Configurable {
+			get;
+			private set;
+		}
+
+		public PluginAttribute(string name, bool configurable)
+        {
+            Name = name;
+			Configurable = configurable;
+		}
+		
+		public int CompareTo(object obj) {
+            if (obj is PluginAttribute other) {
+				return string.Compare(Name, other.Name, StringComparison.Ordinal);
+			}
+			throw new ArgumentException("object is not a PluginAttribute");
+		}
+	}
+}