/usr/share/augeas/lenses/dist/hosts.aug is in augeas-lenses 1.10.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15  | (* Parsing /etc/hosts *)
module Hosts =
  autoload xfm
  let word = /[^# \n\t]+/
  let record = [ seq "host" . Util.indent .
                              [ label "ipaddr" . store  word ] . Sep.tab .
                              [ label "canonical" . store word ] .
                              [ label "alias" . Sep.space . store word ]*
                 . Util.comment_or_eol ]
  let lns = ( Util.empty | Util.comment | record ) *
  let xfm = transform lns (incl "/etc/hosts")
 |