diff -up less-466/less.nro.filters-man less-466/less.nro
--- less-466/less.nro.filters-man	2014-09-18 14:32:32.124111631 +0200
+++ less-466/less.nro	2014-09-18 14:32:39.548177152 +0200
@@ -1323,7 +1323,19 @@ Similarly, if the first two characters of LESSOPEN are vertical bar and dash
 the input pipe is used on standard input as well as other files.
 Again, in this case the dash is not considered to be part of
 the input pipe command.
-.
+.PP
+There are used following files to set up default preprocessor:
+.br
+       /etc/profile.d/less.sh
+.br
+       /etc/profile.d/less.csh
+.br
+These files set up /usr/bin/lesspipe.sh as a default filter. An user defined
+filter can be specified in ~/.lessfilter. This file should have an execute bit
+set and accept only one parameter, which represents a filename. If
+the user defined filter process the file, zero should be returned. Otherwise
+~/.lessfilter tries to handle the file.
+
 .SH "NATIONAL CHARACTER SETS"
 There are three types of characters in the input file:
 .IP "normal characters"