Some site such as mediawiki.org, only allow tranlation to zh, so users set zh-cn or others as their language will fallback to en.
**__Test scope:__**
`c24d9ec` [[https://gerrit.wikimedia.org/g/operations/mediawiki-config/+/master/wmf-config/CommonSettings.php#3075|CommonSettings.php#3075]]
```
$wgTranslateDisabledTargetLanguages = [
'*' => [
'gan-hans' => 'Translate in gan please.',
'gan-hant' => 'Translate in gan please.',
'ike-cans' => 'Translate in iu please.',
'ike-latn' => 'Translate in iu please.',
'kk-cyrl' => 'Translate in kk please.',
'kk-latn' => 'Translate in kk please.',
'kk-arab' => 'Translate in kk please.',
'kk-kz' => 'Translate in kk please.',
'kk-tr' => 'Translate in kk please.',
'kk-cn' => 'Translate in kk please.',
'ku-latn' => 'Translate in ku please.',
'ku-arab' => 'Translate in ku please.',
'shi-tfng' => 'Translate in shi please.',
'shi-latn' => 'Translate in shi please.',
'sr-ec' => 'Translate in sr please.',
'sr-el' => 'Translate in sr please.',
'tg-latn' => 'Translate in tg please.',
'zh-hans' => 'Translate in zh please.',
'zh-hant' => 'Translate in zh please.',
'zh-cn' => 'Translate in zh please.',
'zh-hk' => 'Translate in zh please.',
'zh-mo' => 'Translate in zh please.',
'zh-my' => 'Translate in zh please.',
'zh-sg' => 'Translate in zh please.',
'zh-tw' => 'Translate in zh please.',
],
];
```
**__Current solution:__**
Adding base language to each language variant's fallback chain.
For example, `zh` will be added to `$fallback` in `\languages\messages\MessagesZh_*.php`
**__Current status:__**
```
/* gan-related: Done in zh-related https://gerrit.wikimedia.org/r/c/703560 */
'gan-hans' => 'gan',
'gan-hant' => 'gan',
/* ike-related: To-do */
'ike-cans' => 'iu',
'ike-latn' => 'iu',
/* kk-related: To-do */
'kk-cyrl' => 'kk',
'kk-latn' => 'kk',
'kk-arab' => 'kk',
'kk-kz' => 'kk',
'kk-tr' => 'kk',
'kk-cn' => 'kk',
/* ku-related: To-do */
'ku-latn' => 'ku',
'ku-arab' => 'ku',
/* shi-related: To-do */
'shi-tfng' => 'shi'
'shi-latn' => 'shi',
/* sr-related: To-do */
'sr-ec' => 'sr',
'sr-el' => 'sr',
/* tg-related: To-do */
'tg-latn' => 'tg',
/* zh-related: Done in https://gerrit.wikimedia.org/r/c/703560 */
'zh-hans' => 'zh',
'zh-hant' => 'zh',
'zh-cn' => 'zh',
'zh-hk' => 'zh',
'zh-mo' => 'zh',
'zh-my' => 'zh',
'zh-sg' => 'zh',
'zh-tw' => 'zh',
```
Note: Update [[https://www.mediawiki.org/wiki/File:MediaWiki_fallback_chains.svg|File:MediaWiki_fallback_chains.svg]] as well.