Comment # 1 on bug 1065388 from Dr. Werner Fink

And as root I'm not allowed to read via less and lessopen.sh

 + echo /usr/src/werner/less/less-487/less.1
 + grep -q '^/'
 + SRC=/usr/src/werner/less/less-487/less.1
 + NAME=less.1
 + '[' '!' -r /usr/src/werner/less/less-487/less.1 ']'
 + exit 1

... which is in lessopen.sh

 if echo "$1" | grep -q ^/; then
   # absolute path
   SRC="$1"
 else
   # relative path
   SRC="./$1"
 fi

 NAME="${SRC##*/}"

 [ ! -r "$SRC" ] && exit 1

... this is not what should it be IMHO