Answering my own question (see Manual:$wgForeignFileRepos):
$wgLBFactoryConf = array(
'class' => 'LBFactoryMulti',
'sectionsByDB' => array(
'dewiki' => 's1',
'enwiki' => 's1',
'eswiki' => 's1',
'frwiki' => 's1',
'hiwiki' => 's1',
'itwiki' => 's1',
'jawiki' => 's1',
'plwiki' => 's1',
'ptwiki' => 's1',
'ruwiki' => 's1',
'svwiki' => 's1',
'zhwiki' => 's1',
),
'sectionLoads' => array(
's1' => array(
'localhost' => 0, // All on section s1, which has single master, at localhost.
),
),
'serverTemplate' => array(
'dbname' => $wgDBname,
'user' => $wgDBuser,
'password' => $wgDBpassword,
'type' => 'mysql',
'flags' => DBO_DEFAULT,
'max lag' => 30,
),
);
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'dewiki',
'name' => 'dewiki', # displayname (eg. the vector-skin-tab “View on OtherWiki“) may be set at wiki-specific MediaWiki:Shared-repo-name-<otherwiki>
'url' => 'https://de.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2, # This must be the same for the other family member
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://de.companypedia.net/w', # has effect whether description can be fetched
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'enwiki',
'name' => 'enwiki',
'url' => 'https://en.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://en.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'eswiki',
'name' => 'eswiki',
'url' => 'https://es.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://es.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'frwiki',
'name' => 'frwiki',
'url' => 'https://fr.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://fr.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'hiwiki',
'name' => 'hiwiki',
'url' => 'https://hi.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://hi.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'itwiki',
'name' => 'itwiki',
'url' => 'https://it.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://it.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'jawiki',
'name' => 'jawiki',
'url' => 'https://ja.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://ja.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'plwiki',
'name' => 'plwiki',
'url' => 'https://pl.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://pl.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'ptwiki',
'name' => 'ptwiki',
'url' => 'https://pt.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://pt.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'ruwiki',
'name' => 'ruwiki',
'url' => 'https://ru.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://ru.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'svwiki',
'name' => 'svwiki',
'url' => 'https://sv.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://sv.companypedia.net/w',
];
$wgForeignFileRepos[] = [
'class' => 'ForeignDBViaLBRepo',
'wiki' => 'zhwiki',
'name' => 'zhwiki',
'url' => 'https://zh.companypedia.net/w/images',
'directory' => '/var/www/mediawiki/wiki/w/images',
'hashLevels' => 2,
'tablePrefix' => '',
'hasSharedCache' => false,
'fetchDescription' => true,
'scriptDirUrl' => 'https://zh.companypedia.net/w',
];