diff --git a/PluralKit.Bot/Utils/MentionUtils.cs b/PluralKit.Bot/Utils/MentionUtils.cs
index cd6e9034..73444ce0 100644
--- a/PluralKit.Bot/Utils/MentionUtils.cs
+++ b/PluralKit.Bot/Utils/MentionUtils.cs
@@ -1,9 +1,11 @@
 using System;
 using System.Globalization;
-using System.Text;
 
 namespace PluralKit.Bot.Utils
 {
+    // PK note: class is wholesale copied from Discord.NET (MIT-licensed)
+    // https://github.com/discord-net/Discord.Net/blob/ff0fea98a65d907fbce07856f1a9ef4aebb9108b/src/Discord.Net.Core/Utils/MentionUtils.cs
+    
     /// <summary>
     ///     Provides a series of helper methods for parsing mentions.
     /// </summary>