An example of a pattern with content locking implemented.

content lock pattern

function register_block_patterns() {

	if ( class_exists( 'WP_Block_Patterns_Registry' ) ) {

                $content = '<!-- wp:group {"templateLock":"contentOnly","align":"wide","layout":{"type":"constrained"}} -->
<div class="wp-block-group alignwide"><!-- wp:image {"align":"wide","id":501,"sizeSlug":"full","linkDestination":"none","style":{"color":{"duotone":["#1a4548","#ffffff"]}}} -->
<figure class="wp-block-image alignwide size-full"><img src="https://s.w.org/patterns/files/2021/06/Group-17-scaled.jpg" alt="Image of a woman being carried through the air by swans." class="wp-image-501"/></figure>
<!-- /wp:image -->

<!-- wp:columns {"verticalAlignment":"center","align":"wide"} -->
<div class="wp-block-columns alignwide are-vertically-aligned-center"><!-- wp:column {"verticalAlignment":"center"} -->
<div class="wp-block-column is-vertically-aligned-center"><!-- wp:paragraph {"style":{"typography":{"lineHeight":"2"}}} -->
<p style="line-height:2"><strong>Location:</strong><br>82 Main St. Brooklyn, NY</p>
<!-- /wp:paragraph --></div>
<!-- /wp:column -->

<!-- wp:column {"verticalAlignment":"center"} -->
<div class="wp-block-column is-vertically-aligned-center"><!-- wp:paragraph {"style":{"typography":{"lineHeight":"2"}}} -->
<p style="line-height:2"><strong>Date:</strong><br>October 24, 2021</p>
<!-- /wp:paragraph --></div>
<!-- /wp:column -->

<!-- wp:column {"verticalAlignment":"center"} -->
<div class="wp-block-column is-vertically-aligned-center"><!-- wp:buttons -->
<div class="wp-block-buttons"><!-- wp:button {"backgroundColor":"primary","width":100,"style":{"color":{"text":"#efefef"}}} -->
<div class="wp-block-button has-custom-width wp-block-button__width-100"><a class="wp-block-button__link has-primary-background-color has-text-color has-background wp-element-button" style="color:#efefef">Purchase Tickets</a></div>
<!-- /wp:button --></div>
<!-- /wp:buttons --></div>
<!-- /wp:column --></div>
<!-- /wp:columns --></div>
<!-- /wp:group -->';

		register_block_pattern(
			'custompattern/call-to-action-adventure',
			array(
				'title'         => __( 'Custom Event', 'textdomain' ),
				'description'   => _x( 'A custom event.', 'Block pattern description', 'textdomain' ),
				'content'       => trim($content),
				'categories'    => array( 'buttons' ),
				'keywords'      => array( 'cta' ),
                                'viewportWidth' => 1400,
                                'blockTypes'    => array( 'core/buttons' ),
			)
		);

	}

}
add_action( 'init', 'register_block_patterns' );