Inaccessible hover or focus content (tooltips)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Trail running shoe - Example shop</title>
</head>
<body>
    <header>
        <p>Example shop</p>
    </header>
    <main>
        <h1>Trail running shoe</h1>

        <!-- aria/tab-selected-missing and aria/tabpanel-missing: no tab is
             selected, and the document has no tab panel -->
        <div id="product-tabs" role="tablist" aria-label="Product information">
            <button type="button" role="tab" id="tab-desc">Description</button>
            <button type="button" role="tab" id="tab-reviews">Reviews</button>
        </div>
        <div id="product-text">Lightweight shoe with a grippy sole.</div>

        <!-- aria/combobox-popup-missing: expanded, popup not referenced -->
        <label for="size">Size</label>
        <input id="size" type="text" role="combobox" aria-expanded="true" aria-autocomplete="list">
        <ul id="size-options" role="listbox" aria-label="Sizes">
            <li role="option" id="size-42" aria-selected="false">42</li>
            <li role="option" id="size-43" aria-selected="false">43</li>
        </ul>

        <!-- popover/target-missing and popover/target-invalid -->
        <button type="button" id="guide-btn" popovertarget="size-guide">Size guide</button>
        <button type="button" id="shipping-btn" popovertarget="shipping-info">Shipping</button>
        <div id="shipping-info">Free shipping from 50 EUR.</div>

        <!-- patterns/accordion-controls-missing: expanded, region unknown -->
        <button type="button" id="care-btn" aria-expanded="true">Care instructions</button>
        <div id="care-text">Clean with a damp cloth.</div>
        <div id="fit-btn" role="button" tabindex="0" aria-expanded="true">Fit</div>
        <div id="fit-text">True to size.</div>

        <!-- patterns/tooltip-unreferenced: nothing points at the tooltip -->
        <button type="button" id="fav-btn">Add to wish list</button>
        <div role="tooltip" id="fav-tip">Saved items stay for 30 days</div>

        <!-- modern-attribute-misuse (active_surface_inert): the promotion is
             shown as an open popover but marked inert, so its button cannot be
             reached or operated -->
        <div id="promo" popover="manual" inert aria-label="Promotion">
            <p>10 % off your first order.</p>
            <button type="button" id="promo-close">Close</button>
        </div>
    </main>
    <footer>
        <p>Example shop</p>
    </footer>
    <script>
        document.getElementById('promo').showPopover();
    </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Trail running shoe - Example shop</title>
</head>
<body>
    <header>
        <p>Example shop</p>
    </header>
    <main>
        <h1>Trail running shoe</h1>

        <!-- One tab selected, panel present -->
        <div id="product-tabs" role="tablist" aria-label="Product information">
            <button type="button" role="tab" id="tab-desc" aria-selected="true" aria-controls="panel-desc">Description</button>
            <button type="button" role="tab" id="tab-reviews" aria-selected="false" aria-controls="panel-desc" tabindex="-1">Reviews</button>
        </div>
        <div id="panel-desc" role="tabpanel" aria-labelledby="tab-desc">Lightweight shoe with a grippy sole.</div>

        <!-- Expanded combobox referencing its popup; a collapsed one needs no
             reference -->
        <label for="size">Size</label>
        <input id="size" type="text" role="combobox" aria-expanded="true" aria-autocomplete="list" aria-controls="size-options">
        <ul id="size-options" role="listbox" aria-label="Sizes">
            <li role="option" id="size-42" aria-selected="false">42</li>
            <li role="option" id="size-43" aria-selected="false">43</li>
        </ul>
        <label for="colour">Colour</label>
        <input id="colour" type="text" role="combobox" aria-expanded="false" aria-autocomplete="list">

        <!-- The native select has its popup built in -->
        <label for="qty">Quantity</label>
        <select id="qty"><option>1</option><option>2</option></select>

        <!-- A visible menu named by its heading -->
        <h2 id="sort-label">Sort reviews</h2>
        <div id="sort-menu" role="menu" aria-labelledby="sort-label">
            <div role="menuitem" id="sort-new" tabindex="0">Newest first</div>
            <div role="menuitem" id="sort-best" tabindex="-1">Best rated</div>
        </div>

        <!-- popovertarget points at a (closed, hence hidden) popover -->
        <button type="button" id="guide-btn" popovertarget="size-guide">Size guide</button>
        <div id="size-guide" popover>EU 42 equals UK 8.</div>

        <!-- Expanded button naming the region it controls -->
        <button type="button" id="care-btn" aria-expanded="true" aria-controls="care-text">Care instructions</button>
        <div id="care-text">Clean with a damp cloth.</div>

        <!-- Tooltips referenced as description and as name -->
        <button type="button" id="fav-btn" aria-describedby="fav-tip">Add to wish list</button>
        <div role="tooltip" id="fav-tip">Saved items stay for 30 days</div>
        <button type="button" id="share-btn" aria-labelledby="share-tip"><span aria-hidden="true">&#x2197;</span></button>
        <div role="tooltip" id="share-tip">Share</div>

        <!-- Open, operable popover -->
        <div id="promo" popover="manual" aria-label="Promotion">
            <p>10 % off your first order.</p>
            <button type="button" id="promo-close">Close</button>
        </div>
    </main>
    <footer>
        <p>Example shop</p>
    </footer>
    <script>
        document.getElementById('promo').showPopover();
    </script>
</body>
</html>