也许有某种API可用

Yes, there is, 你可以去看看here.

这里有一些链接自该Codex页面的示例，您可能希望使用版本1.2(GET （仅请求）或API的1.1版本，其中这两个版本的响应格式均为JSON。

实际上，还有plugins_api() 让事情变得容易；但是，您需要手动加载定义函数的文件(wp-admin/includes/plugin-install.php).

示例使用plugins_api()

// You may comment this out IF you\'re sure the function exists.
require_once ABSPATH . \'wp-admin/includes/plugin-install.php\';

$args = [
    \'slug\' => \'woocommerce\',
];

$data = plugins_api( \'plugin_information\', $args );
//var_dump( $data );

if ( $data && ! is_wp_error( $data ) ) {
    echo \'Latest version: \' . $data->version;
}

手动HTTP请求示例

$args = [
    \'slug\' => \'woocommerce\',
];

$url = \'http://api.wordpress.org/plugins/info/1.2/\';
$url = add_query_arg( [
    \'action\'  => \'plugin_information\', // first param for plugins_api()
    \'request\' => $args,                // second param for plugins_api()
], $url );

$res = wp_remote_get( $url );
if ( ! is_wp_error( $res ) ) {
    $data = json_decode( wp_remote_retrieve_body( $res ) );
    //var_dump( $data );
    echo \'Latest version: \' . $data->version;
}

$args = [
    \'slug\' => \'woocommerce\',
    \'fields\' => [
        \'sections\' => false, // excludes all readme sections
        \'reviews\'  => false, // excludes all reviews
    ],
];