diff --git a/runtime/doc/diff.txt b/runtime/doc/diff.txt
index e3d8f53..d72f37e 100644
--- a/runtime/doc/diff.txt
+++ b/runtime/doc/diff.txt
@@ -1,4 +1,4 @@
-*diff.txt*      For Vim version 8.2.  Last change: 2021 May 24
+*diff.txt*      For Vim version 8.2.  Last change: 2022 Jan 22
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -335,8 +335,9 @@
 
 FINDING THE DIFFERENCES					*diff-diffexpr*
 
-The 'diffexpr' option can be set to use something else than the standard
-"diff" program to compare two files and find the differences. *E959*
+The 'diffexpr' option can be set to use something else than the internal diff
+support or the standard "diff" program to compare two files and find the
+differences. *E959*
 
 When 'diffexpr' is empty, Vim uses this command to find the differences
 between file1 and file2: >
@@ -369,7 +370,7 @@
 
 	v:fname_in		original file
 	v:fname_new		new version of the same file
-	v:fname_out		resulting diff file
+	v:fname_out		where to write the resulting diff file
 
 Additionally, 'diffexpr' should take care of "icase" and "iwhite" in the
 'diffopt' option.  'diffexpr' cannot change the value of 'lines' and
@@ -402,7 +403,9 @@
 with the script ID (|local-function|). Example: >
 		set diffexpr=s:MyDiffExpr()
 		set diffexpr=<SID>SomeDiffExpr()
-<
+Otherwise, the expression is evaluated in the context of the script where the
+option was set, thus script-local items are available.
+
 						*E810* *E97*
 Vim will do a test if the diff output looks alright.  If it doesn't, you will
 get an error message.  Possible causes:
@@ -458,5 +461,8 @@
 with the script ID (|local-function|). Example: >
 		set patchexpr=s:MyPatchExpr()
 		set patchexpr=<SID>SomePatchExpr()
-<
+Otherwise, the expression is evaluated in the context of the script where the
+option was set, thus script-local items are available.
+
+
  vim:tw=78:ts=8:noet:ft=help:norl: