GNU Midnight Commander 4.8.24
Built with GLib 2.50.3
Using the S-Lang library with terminfo database
With builtin Editor and Aspell support
With subshell support as default
With support for background operations
With mouse support on xterm and Linux console
With support for X11 events
With internationalization support
With multiple codepages support
Virtual File Systems: cpiofs, tarfs, sfs, extfs, ftpfs, sftpfs, fish
Data types: char: 8; int: 32; long: 32; void *: 32; size_t: 32; off_t: 64;

GNU Midnight Commander 4.8.24
Built with GLib 2.26.1
Using the S-Lang library with terminfo database
With builtin Editor and Aspell support
With subshell support as default
With support for background operations
With mouse support on xterm and Linux console
With support for X11 events
With internationalization support
With multiple codepages support
Virtual File Systems: cpiofs, tarfs, sfs, extfs, ftpfs, sftpfs, fish, smbfs
Data types: char: 8; int: 32; long: 32; void *: 32; size_t: 32; off_t: 64;

Built with GLib 2.26.1

cat /usr/libexec/mc/ext.d/web.sh
#!/bin/sh

# $1 - action
# $2 - type of file

action=$1
filetype=$2

[ -n "${MC_XDG_OPEN}" ] || MC_XDG_OPEN="xdg-open"

do_view_action() {
    filetype=$1

    case "${filetype}" in
    html)
        links -dump "${MC_EXT_FILENAME}" 2>/dev/null || \
            w3m -dump "${MC_EXT_FILENAME}" 2>/dev/null || \
            lynx -dump -force_html "${MC_EXT_FILENAME}"
        ;;
    *)
        ;;
    esac
}

####
# дальше вырезано

lynx-2.8.7-x86-sl12.2
links-2.12-i486-sl12.2

links-2.14

do_view_action() {
    filetype=$1

    case "${filetype}" in
    html)
        links -dump             "${MC_EXT_FILENAME}" 2>/dev/null || \
        w3m   -dump             "${MC_EXT_FILENAME}" 2>/dev/null || \
        lynx  -dump -force_html "${MC_EXT_FILENAME}" 2>/dev/null ||
        cat                     "${MC_EXT_FILENAME}"
...
-->
cat ...

# html
regex/i/\.html?$
        Open=/usr/lib/mc/ext.d/web.sh open html
        View=%view{ascii} /usr/lib/mc/ext.d/web.sh view html

[ -n "${MC_XDG_OPEN}" ] || MC_XDG_OPEN="xdg-open"

do_view_action() {
    filetype=$1

    case "${filetype}" in
    html)
        links -dump "${MC_EXT_FILENAME}" 2>/dev/null || \
            w3m -dump "${MC_EXT_FILENAME}" 2>/dev/null || \
            lynx -dump -force_html "${MC_EXT_FILENAME}" 2>/dev/null ||
            cat "${MC_EXT_FILENAME}"
        ;;
    *)
        ;;
    esac
}

cat 1.html | iconv -f cp1251

/usr/libexec/mc/ext.d/web.sh

enconv -L ru_RU.UTF-8 < 1.html > 1.ru
lynx -display_charset=utf-8 -force_html 1.ru

O - options
Assumed document character set(!): [utf-8___________]

"Accept Changes" (потом стрелка вправо - сохранить)

Save options to disk: [X] (стрелка вправо)

Assumed document character set(!): [iso-8859-1______]
options marked with (!) will not be saved

lynx --help | grep charset
-assume_charset       = MIMEname charset for documents that don't specify it
-assume_local_charset = MIMEname charset assumed for local files
-assume_unrec_charset = MIMEname use this instead of unrecognized charsets
-display_charset      = MIMEname charset for the terminal output
-html5_charsets         toggles use of HTML5 charset replacements (off)

lynx -display_charset=UTF8 -assume_charset=utf-8 -force_html  1.ru

enconv -L ru_RU.UTF-8 < 1.html | lynx -dump -force_html -stdin -display_charset=UTF8 -assume_charset=utf-8

sudo mcedit /usr/libexec/mc/ext.d/web.sh

do_view_action() {
  filetype=$1

  case "${filetype}" in
  html)
  enconv -L ru_RU.UTF-8 <  "${MC_EXT_FILENAME}" | lynx -dump -force_html -stdin -display_charset=UTF8 -assume_charset=utf-8 2>/dev/null || \
  lynx  -dump -force_html  "${MC_EXT_FILENAME}" 2>/dev/null || \
  links -dump              "${MC_EXT_FILENAME}" 2>/dev/null || \
  w3m   -dump              "${MC_EXT_FILENAME}" 2>/dev/null || \
  cat                      "${MC_EXT_FILENAME}";;
    *) ;;
  esac
}

    <meta
     http-equiv="Content-Type"
     content="text/html; charset=koi8-r">
    <meta

charset=<любое значение>
заменять
charset=utf-8

charset=koi8-r
менять
charset=utf-8

#!/bin/sh
set -e; clear

HTM=test.htm
CHARSET_DISPLAY=UTF8
 CHARSET_ASSUME=utf-8

#
# ищем charset=koi8-r">
#

enconv -L ru_RU.UTF-8 < $HTM | \
sed -e "s%charset=koi8-r%charset=$CHARSET_ASSUME%" | \
lynx -dump -force_html -stdin -display_charset=UTF8 -assume_charset=utf-8

sed -z 's/charset=koi8-r/charset=utf-8/' 

-z, --null-data separate lines by NUL characters

charset=<любое значение>
заменять
charset=utf-8