wordpressのプラグイン「Gwolle Guestbook 」でHTMLを投稿できるようにしたい。

wordpressのプラグイン「Gwolle Guestbook 」でHTMLを投稿できるようにしたいのですが、
方法がわからず悩んでいます。

どのコードがHTMLを無効にさせているのか、教えていただけるとありがたいです。
よろしくおねがいします。

https://ja.wordpress.org/plugins/gwolle-gb/

試したこと：remove_actionで削除できるフックがないか探してみたがわからなかった。

php
1<?php
2
3
4// No direct calls to this script
5if ( strpos($_SERVER['PHP_SELF'], basename(__FILE__) )) {
6	die('No direct calls allowed!');
7}
8
9
10/*
11 * Set meta_keys so we can find the post with the shortcode back.
12 *
13 * @param int $id ID of the post
14 */
15function gwolle_gb_save_post($id) {
16
17	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
18		return;
19	if ( defined( 'DOING_AJAX' ) && DOING_AJAX )
20		return;
21	if ( defined( 'DOING_CRON' ) && DOING_CRON )
22		return;
23
24	if ( function_exists('has_shortcode') ) {
25		$post = get_post( $id );
26
27		if ( has_shortcode( $post->post_content, 'gwolle_gb' ) || has_shortcode( $post->post_content, 'gwolle_gb_read' ) ) {
28			// Set a meta_key so we can find the post with the shortcode back.
29			$meta_value = get_post_meta( $id, 'gwolle_gb_read', true );
30			if ( $meta_value != 'true' ) {
31				update_post_meta( $id, 'gwolle_gb_read', 'true' );
32			}
33		} else {
34			// Remove the meta_key in case it is set.
35			delete_post_meta( $id, 'gwolle_gb_read' );
36		}
37
38		if ( has_shortcode( $post->post_content, 'gwolle_gb' ) || has_shortcode( $post->post_content, 'gwolle_gb_read' ) || has_shortcode( $post->post_content, 'gwolle_gb_write' ) ) {
39			// Nothing to do
40		} else {
41			delete_post_meta( $id, 'gwolle_gb_book_id' );
42		}
43	}
44}
45add_action('save_post', 'gwolle_gb_save_post');
46
47
48/*
49 * Set meta_keys so we can find the post with the shortcode back.
50 *
51 * @param string $content Content of the post
52 * @return string $content Content of the post
53 *
54 * @since 3.1.8
55 */
56function gwolle_gb_content_filter_for_meta_keys( $content ) {
57
58	if ( ! is_singular() || ! is_main_query() || is_admin() ) {
59		return $content;
60	}
61
62	if ( function_exists('has_shortcode') ) {
63		$id = get_the_ID();
64
65		if ( has_shortcode( $content, 'gwolle_gb' ) || has_shortcode( $content, 'gwolle_gb_read' ) ) {
66			// Set a meta_key so we can find the post with the shortcode back.
67			$meta_value = get_post_meta( $id, 'gwolle_gb_read', true );
68			if ( $meta_value != 'true' ) {
69				update_post_meta( $id, 'gwolle_gb_read', 'true' );
70			}
71		} else {
72			// Remove the meta_key in case it is set.
73			delete_post_meta( $id, 'gwolle_gb_read' );
74		}
75
76		if ( has_shortcode( $content, 'gwolle_gb' ) || has_shortcode( $content, 'gwolle_gb_read' ) || has_shortcode( $content, 'gwolle_gb_write' ) ) {
77			// Nothing to do
78		} else {
79			delete_post_meta( $id, 'gwolle_gb_book_id' );
80		}
81	}
82
83	return $content;
84}
85add_filter( 'the_content', 'gwolle_gb_content_filter_for_meta_keys', 1 ); // before shortcodes are done.
86
87/*
88 * Make our meta fields protected, so they are not in the custom fields metabox.
89 *
90 * @since 2.1.5
91 */
92function gwolle_gb_is_protected_meta( $protected, $meta_key, $meta_type ) {
93
94	switch ($meta_key) {
95		case 'gwolle_gb_read':
96			return true;
97		case 'gwolle_gb_book_id':
98			return true;
99	}
100
101	return $protected;
102}
103add_filter( 'is_protected_meta', 'gwolle_gb_is_protected_meta', 10, 3 );
104
105
106/*
107 * Set Meta_keys so we can find the post with the shortcode back.
108 * Gets called from frontend/gb-shortcodes.php.
109 *
110 * @param string $shortcode      value 'write' or 'read'.
111 * @param array  $shortcode_atts array with the shortcode attributes.
112 *
113 * @since      1.5.6
114 * @deprecated 3.1.8 Meta keys are now set in gwolle_gb_content_filter_for_meta_keys()
115 */
116function gwolle_gb_set_meta_keys( $shortcode, $shortcode_atts ) {
117
118	_deprecated_function( __FUNCTION__, ' 3.1.8', 'gwolle_gb_content_filter_for_meta_keys()' );
119	return;
120
121}
122
123
124/*
125 * Check whether this post/page is a guestbook.
126 * Will test if the 'gwolle_gb_read' meta key is set to 'true'.
127 *
128 * @param  bool $post_id the ID of the post to check.
129 * @return bool          true if this post has a guestbook shortcode.
130 *
131 * @since 3.0.0
132 */
133function gwolle_gb_post_is_guestbook( $post_id ) {
134
135	$meta_value_read = get_post_meta( $post_id, 'gwolle_gb_read', true );
136	if ( $meta_value_read == 'true' ) {
137		return true;
138	}
139
140	return false;
141
142}
143