正则表达式从字符串中删除xml声明

^<\?xml.*?\?>

const str = '<?xml version="1.0" encoding="UTF-8"?>Some content';
const regex = /^<\?xml.*?\?>/;

const result = str.replace(regex, '');
console.log(result);

import re

str = '<?xml version="1.0" encoding="UTF-8"?>Some content'
regex = r'^<\?xml.*?\?>'

result = re.sub(regex, '', str)
print(result)

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class Main {
    public static void main(String[] args) {
        String str = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>Some content";
        String regex = "^<\\?xml.*?\\?>";

        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(str);
        String result = matcher.replaceAll("");

        System.out.println(result);
    }
}