querySelectorAll with multiple selectors returns the elements in source order. So the following HTML:
<h1> h1 </h1>
<h2> h2 </h2>
<h3> h3 </h3>
<h2> h2 </h2>
<h3> h3 </h3>
Combined with this javascript: document.querySelectorAll("h1, h2, h3"); will return [h1, h2, h3, h2, h3]. The equivalent querySelectorAllDeep however returns those listed selector by selector: [h1, h2, h2, h3, h3]. That can be quite an important difference. Is that worth fixing (I guess that might be difficult) or at least mentioning in the readme?