weechat/doc/en/autogen/user/charset_options.txt

* [[option_charset.default.decode]] *charset.default.decode*
** description: `global decoding charset: charset used to decode incoming messages (if decoding fails, fallback is UTF-8 because it is the WeeChat internal charset)`
** type: string
** values: any string (default value: `"iso-8859-1"`)

* [[option_charset.default.encode]] *charset.default.encode*
** description: `global encoding charset: charset used to encode outgoing messages (if empty, default is UTF-8 because it is the WeeChat internal charset)`
** type: string
** values: any string (default value: `""`)