diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 9442996..2e89098 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -5803,6 +5803,10 @@
 		strtod() function to parse numbers, Strings, Lists, Dicts and
 		Funcrefs will be considered as being 0).
 
+		When {func} is given and it is 'N' then all items will be
+		sorted numerical. This is like 'n' but a string containing
+		digits will be used as the number they represent.
+
 		When {func} is a |Funcref| or a function name, this function
 		is called to compare items.  The function is invoked with two
 		items as argument and must return zero if they are equal, 1 or
@@ -5817,6 +5821,11 @@
 		on numbers, text strings will sort next to each other, in the
 		same order as they were originally.
 
+		The sort is stable, items which compare equal (as number or as
+		string) will keep their relative position. E.g., when sorting
+		on numbers, text strings will sort next to each other, in the
+		same order as they were originally.
+
 		Also see |uniq()|.
 
 		Example: >