What does this alphabetized css selectors mean?

Question

I have seen from time to time this alphabetized css selector. Why would someone use a selector like that? Where did it come from? Why can't we just use * selector to select all?

------ update ------

After seeing 2 answers now the question becomes what element is left out, i.e. what element does not need to be normalized?

Thanks.

a, abbr, acronym, address, applet, article, aside, audio, b, big, blockquote, body, canvas,
caption,center, cite,code, dd, del, details, dfn, div, dl, dt, em,embed, fieldset, figcaption, 
figure, footer, form, h1, h2, h3, h4, h5, h6, header, hgroup, html, i, iframe, img, ins, 
kbd, label, legend, li, mark, menu, nav, object, ol, output, p,pre, q, ruby, s, samp, 
section,small, span, strike, strong,sub, summary, sup, table, tbody, td, tfoot, th, thead, 
 time, tr, tt, u, ul, var, video {
    margin:0;
    padding:0;
    border:0;
    font: inherit;
    ...
}

Answer 1

This is called normalization,each ٍelement may have properties as defaults in different browsers,normalization makes browsers render all elements more consistently.

h1,h2,.....,a {
  my rules;
}

For Example,h1...h5 elemets have some margin as default. we don't want this margin for it,so change it.see this example:

h1,h2 {
  background-color: orange;
  border: 1px solid;
}

.def {
  margin: 0;
}

Default without change <b>margin</b>.<i>h1</i> and <i>h2</i> have margin as default:
<h1>Default H1</h1>
<h2>Default H2</h2>

Changed:
<h1 class="def">Default H1</h1>
<h2 class="def">Default H2</h2>

* Selector, selects all things, but we must select elements that need change it default properties.

Answer 2

This CSS code generally corresponds to code inside a CSS framework like Bootstrap to normalize and standardize browser output of HTML elements, as for default, browsers rendering engines have associated properties assigned for certain elements, applying this certain CSS rules allows a page to render a more consistent output on most browsers. Some browsers present some "bugs" or particular behaviours with their rendering engines and this CSS stylesheets aim to fix or "reset" the css rules for HTML tags. A very common "resetting" CSS component that is used is normalize.css, you can learn more about it here.

As for why the * selector its not used, I think it would be because not all this fixes correspond to all HTML tags, and also if new HTML tags are supported or included on the HTML specifications, applying a global style to all elements could make them behave incorrectly. Hopefully someone could expand on my answer to make it more complete.

EDIT

As this question intrigued me, it is interesting to check how the universal * selector is intended to assign properties to CSS namespaces, but a potentially wrong implementation for older/mobile browsers could lead to unknown issues, you could refer to the definition of "universal selector" on this links:

MSDN definition on Universal Selectors

W3C Definition on Universal Selectors and appliance

Browser implementations of Universal Selectors (check known issues tab)