diff --git a/core/lib/utils/mail/mail_address.dart b/core/lib/utils/mail/mail_address.dart
index ad2b1f4db7..276b701755 100644
--- a/core/lib/utils/mail/mail_address.dart
+++ b/core/lib/utils/mail/mail_address.dart
@@ -166,6 +166,8 @@ class MailAddress with EquatableMixin {
   }
 
   String strictUrlEncode(String input) {
+    // cannot use Uri.encodeComponent because it is meant to be compliant with RFC2396
+    // eg `-_.!~*'()` are not encoded (but we want them to)
     final StringBuffer encoded = StringBuffer();
 
     for (int codeUnit in utf8.encode(input)) {