Filter the source language sent to translation APIs
This provides an alternative way to change the source language that gets posted to translation APIs.
Setting the "src" key via loco_api_providers takes priority, but this filter has the advantage that the PO file being translated is also available.
This example changes the source language for only a specific text domain:
function filter_loco_api_provider_source( $tag, $path ){
if( 'german-theme' === substr(basename($path),0,12) ){
$tag = 'de';
}
return $tag;
}
add_filter('loco_api_provider_source','filter_loco_api_provider_source',999,2);