A Javascript script prints headers in current HTML file with tabs representing their depth.

extract_headers.js

class Tag {
    constructor(level, text) {
        this.level = level;
        this.text = text;
    };
};

function extractHeaders() {
    const headers = document.querySelectorAll('h1, h2, h3, h4, h5, h6');
    console.log(headers);
    const tagList = Array.from(headers).map(header => {
        const level = parseInt(header.tagName.substring(1));
        const text = header.innerText.trim();
        return new Tag(level, text);
    });

    tagList.forEach(tag => {
        const indentation = '\t'.repeat(tag.level);
        console.log(`${indentation}${tag.text}`);
    });

    return tagList;
};

extractHeaders();