empty; `null` otherwise.
	 */
	function array_key_first( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
		foreach ( $array as $key => $value ) {
			return $key;
		}
	}
}

if ( ! function_exists( 'array_key_last' ) ) {
	/**
	 * Polyfill for `array_key_last()` function added in PHP 7.3.
	 *
	 * Get the last key of the given array without affecting the
	 * internal array pointer.
	 *
	 * @since 5.9.0
	 *
	 * @param array $array An array.
	 * @return string|int|null The last key of array if the array
	 *.                        is not empty; `null` otherwise.
	 */
	function array_key_last( array $array ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound
		if ( empty( $array ) ) {
			return null;
		}

		end( $array );

		return key( $array );
	}
}

if ( ! function_exists( 'array_is_list' ) ) {
	/**
	 * Polyfill for `array_is_list()` function added in PHP 8.1.
	 *
	 * Determines if the given array is a list.
	 *
	 * An array is considered a list if its keys consist of consecutive numbers from 0 to count($array)-1.
	 *
	 * @see https://github.com/symfony/polyfill-php81/tree/main
	 *
	 * @since 6.5.0
	 *
	 * @param array<mixed> $arr The array being evaluated.
	 * @return bool True if array is a list, false otherwise.
	 */
	function array_is_list( $arr ) {
		if ( ( array() === $arr ) || ( array_values( $arr ) === $arr ) ) {
			return true;
		}

		$next_key = -1;

		foreach ( $arr as $k => $v ) {
			if ( ++$next_key !== $k ) {
				return false;
			}
		}

		return true;
	}
}

if ( ! function_exists( 'str_contains' ) ) {
	/**
	 * Polyfill for `str_contains()` function added in PHP 8.0.
	 *
	 * Performs a case-sensitive check indicating if needle is
	 * contained in haystack.
	 *
	 * @since 5.9.0
	 *
	 * @param string $haystack The string to search in.
	 * @param string $needle   The substring to search for in the `$haystack`.
	 * @return bool True if `$needle` is in `$haystack`, otherwise false.
	 */
	function str_contains( $haystack, $needle ) {
		if ( '' === $needle ) {
			return true;
		}

		return false !== strpos( $haystack, $needle );
	}
}

if ( ! function_exists( 'str_starts_with' ) ) {
	/**
	 * Polyfill for `str_starts_with()` function added in PHP 8.0.
	 *
	 * Performs a case-sensitive check indicating if
	 * the haystack begins with needle.
	 *
	 * @since 5.9.0
	 *
	 * @param string $haystack The string to search in.
	 * @param string $needle   The substring to search for in the `$haystack`.
	 * @return bool True if `$haystack` starts with `$needle`, otherwise false.
	 */
	function str_starts_with( $haystack, $needle ) {
		if ( '' === $needle ) {
			return true;
		}

		return 0 === strpos( $haystack, $needle );
	}
}

if ( ! function_exists( 'str_ends_with' ) ) {
	/**
	 * Polyfill for `str_ends_with()` function added in PHP 8.0.
	 *
	 * Performs a case-sensitive check indicating if
	 * the haystack ends with needle.
	 *
	 * @since 5.9.0
	 *
	 * @param string $haystack The string to search in.
	 * @param string $needle   The substring to search for in the `$haystack`.
	 * @return bool True if `$haystack` ends with `$needle`, otherwise false.
	 */
	function str_ends_with( $haystack, $needle ) {
		if ( '' === $haystack ) {
			return '' === $needle;
		}

		$len = strlen( $needle );

		return substr( $haystack, -$len, $len ) === $needle;
	}
}

// IMAGETYPE_WEBP constant is only defined in PHP 7.1 or later.
if ( ! defined( 'IMAGETYPE_WEBP' ) ) {
	define( 'IMAGETYPE_WEBP', 18 );
}

// IMG_WEBP constant is only defined in PHP 7.0.10 or later.
if ( ! defined( 'IMG_WEBP' ) ) {
	define( 'IMG_WEBP', IMAGETYPE_WEBP );
}

// IMAGETYPE_AVIF constant is only defined in PHP 8.x or later.
if ( ! defined( 'IMAGETYPE_AVIF' ) ) {
	define( 'IMAGETYPE_AVIF', 19 );
}

// IMG_AVIF constant is only defined in PHP 8.x or later.
if ( ! defined( 'IMG_AVIF' ) ) {
	define( 'IMG_AVIF', IMAGETYPE_AVIF );
}
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function str_contains() in /home/sportuga/public_html/wp-includes/load.php:1641
Stack trace:
#0 /home/sportuga/public_html/wp-includes/default-constants.php(43): wp_convert_hr_to_bytes('512m')
#1 /home/sportuga/public_html/wp-settings.php(63): wp_initial_constants()
#2 /home/sportuga/public_html/wp-config.php(102): require_once('/home/sportuga/...')
#3 /home/sportuga/public_html/wp-load.php(50): require_once('/home/sportuga/...')
#4 /home/sportuga/public_html/wp-blog-header.php(13): require_once('/home/sportuga/...')
#5 /home/sportuga/public_html/index.php(17): require('/home/sportuga/...')
#6 {main}
  thrown in <b>/home/sportuga/public_html/wp-includes/load.php</b> on line <b>1641</b><br />