Theme checker results

I done a check on this theme to see if it was safe to use.

The results returned, I don’t really understand and looking for some advice on how to at least correct some of these errors.

Below is the results from theme checker.

Anyone advise?
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WARNING: curl_init was found in the file js/sharrre.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.
Line 53: $ch = curl_init();
WARNING: curl_exec was found in the file js/sharrre.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.
Line 58: $content = curl_exec($ch);
RECOMMENDED: Possible variable $this found in translation function in functions/class-tgm-plugin-activation.php. Translation function calls must NOT contain PHP variables.
Line 369: <?php if ( isset( $this->message ) ) _e( wp_kses_post( $this->message ), ‘tgmpa’ ); ?>
RECOMMENDED: No reference to add_theme_support( “custom-header”, $args ) was found in the theme. It is recommended that the theme implement this functionality if using an image for the header.
RECOMMENDED: No reference to add_theme_support( “custom-background”, $args ) was found in the theme. If the theme uses background images or solid colors for the background, then it is recommended that the theme implement this functionality.
RECOMMENDED: No reference to add_editor_style() was found in the theme. It is recommended that the theme implement editor styling, so as to make the editor content match the resulting post output in the theme, for a better user experience.
INFO: Possible hard-coded links were found in the file functions/theme-options.php.
Line 30:

• Download the sample child theme here

Line 904: ‘desc’ => ‘Font Awesome icon names [V
INFO: Possible hard-coded links were found in the file functions/theme-options.php.
Line 30:

• Download the sample child theme here

INFO: Non-printable characters were found in the functions/theme-options.php file. You may want to check this file for errors.
Line 37: <p>You can support the theme author by donating here ��� any amount is always appreciated.</p>
INFO: option-tree/ot-loader.php The theme appears to use include or require. If these are being used to include separate sections of a template from independent files, then get_template_part() should be used instead.
Line 541: include_once( $file );
INFO: option-tree/includes/ot-functions-docs-page.php The theme appears to use include or require. If these are being used to include separate sections of a template from independent files, then get_template_part() should be used instead.
Line 727: require( trailingslashit( get_template_directory() ) . \’includes/meta-boxe
Line 810: require( trailingslashit( get_template_directory() ) . \’option-tree/ot-loa
Line 827: require( trailingslashit( get_template_directory() ) . \’includes/theme-opt
INFO: functions/class-tgm-plugin-activation.php The theme appears to use include or require. If these are being used to include separate sections of a template from independent files, then get_template_part() should be used instead.
Line 983: require_once( ABSPATH . ‘wp-admin/includes/class-wp-list-table.php’ );

Thanks in advance.
Aaron.