Reveal anchor links on websites. To add this to your bookmarks (bar), bookmark this page, copy the script below, edit the bookmark and change the address to the script.

anchor_bookmarklet.js

javascript: (() => {
    var anchorTest = 'bookmarklet-anchor-test';
    if (document.getElementById(anchorTest)) {
        alert("Anchors already present");
        return;
    }

    function createAnchor(anchorId) {
        var anchor = document.createElement('a');
        anchor.href = '#' + anchorId;
        anchor.innerText = '⚓️';
        anchor.style = 'margin-right: 0.3em';
        return anchor;
    }
    var headings = ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'];
    var headingsWithId = headings.map(heading => `${heading}[id]`).join(' ');
    var anchorLinks = document.querySelectorAll(headingsWithId);
    var foundAnchors = anchorLinks.length > 0;
    anchorLinks.forEach(heading => {
        var anchor = createAnchor(heading.getAttribute('id'));
        heading.insertBefore(anchor, heading.firstChild);
    });
    var isAppleSupportSite = window.location.origin.includes('support.apple.com');
    if (isAppleSupportSite || !foundAnchors) {
        var documentRoot = document;
        ['.main', '#article-section'].forEach(nodeSearch => {
            if (documentRoot.querySelector(nodeSearch)) {
                documentRoot = documentRoot.querySelector(nodeSearch)
            }
        });
        var anchorLinks = Array.from(documentRoot.querySelectorAll('[id]'));
        var mappedIds = [];
        anchorLinks.filter(anchorLink => {
                var anchorLinkId = anchorLink.id;
                if (
                    mappedIds.includes(anchorLinkId) ||
                    mappedIds.includes(anchorLinkId.replace('aria-', ''))
                ) {
                    return false;
                }
                mappedIds.push(anchorLinkId);
                return true;
            })
            .forEach(anchorLink => {
                var anchorLinkId = anchorLink.id;
                var anchor = createAnchor(anchorLinkId);
                var anchorPoint = null;
                var i = 0;
                while (anchorPoint === null && i < headings.length) {
                    anchorPoint = anchorLink.querySelector(headings[i]) ?? null;
                    i++;
                }
                if (!anchorPoint) {
                    anchorPoint = anchorLink.children.item(0);
                } else if (anchorPoint.querySelector('button')) {
                    while ((anchorPoint.children ?? []).length > 0 && anchorPoint.innerText) {
                        anchorPoint = anchorPoint.firstChild;
                    }
                    anchorPoint.parentNode.insertBefore(anchor, anchorPoint);
                } else {
                    anchorPoint.insertBefore(anchor, anchorPoint.firstChild);
                }
            });
    }
    var testSpan = document.createElement('span');
    testSpan.setAttribute('id', anchorTest);
    document.body.appendChild(testSpan);
})();