diff --git a/doc/content-for-reference.html b/doc/content-for-reference.html
index acc9b9331..245e2a8eb 100644
--- a/doc/content-for-reference.html
+++ b/doc/content-for-reference.html
@@ -1337,35 +1337,21 @@ by design handles heterogenous data: the running @sum in
mlr put '@sum += $x'
should not be invalidated for records which have no x.
- Absent out-of-stream-variable values are precisely what allow you to write not
-mlr put 'begin{@sum = 0}; @sum += $x'
-but rather
-mlr put '@sum += $x'
-— and furthermore make it possible for you to write
-mlr put '@sum[$a] += $x'
-at all.
+ Absent out-of-stream-variable values are precisely what allow you to write
+mlr put '@sum += $x'. Otherwise you would have to write
+mlr put 'begin{@sum = 0}; @sum += $x' —
+which is tolerable — but for
+mlr put 'begin{...}; @sum[$a][$b] += $x'
+you’d have to pre-initialize @sum for all values of $a and $b in your
+input data stream, which is intolerable.
-
-
- The penalty for this is that misspelled variables can be hard to find:
+ The penalty for the absent feature is that misspelled variables can be hard to find:
e.g. in mlr put 'begin{@sumx = 10}; ...; update @sumx somehow per-record; ...; end {@something = @sum * 2}'
the accumulator is spelt @sumx in the begin-block but @sum in the end-block, where since it
is absent, @sum*2 evaluates to 2.
-
-
-
- The penalty for this is that misspelled variables can be hard to find:
+ The penalty for the absent feature is that misspelled variables can be hard to find:
e.g. in mlr put 'begin{@sumx = 10}; ...; update @sumx somehow per-record; ...; end {@something = @sum * 2}'
the accumulator is spelt @sumx in the begin-block but @sum in the end-block, where since it
is absent, @sum*2 evaluates to 2.