[icons] How to use the new Material Design Icon themes: Outlined, Rounded, Two-Tone and Sharp?

None of the answers so far explains how to download the various variants of that font so that you can serve them from your own website (WWW server).

While this might seem like a minor issue from the technical perspective, it is a big issue from the legal perspective, at least if you intend to present your pages to any EU citizen (or even, if you do that by accident). This is even true for companies which reside in the US (or any country outside the EU).

If anybody is interested why this is, I'll update this answer and give some more details here, but at the moment, I don't want to waste too much space off-topic.

Having said this:

I've downloaded all versions (regular, outlined, rounded, sharp, two-tone) of that font following two very easy steps (it was @Aj334's answer to his own question which put me on the right track) (example: "outlined" variant):

1. Get the CSS from the Google CDN by directly letting your browser fetch the CSS URL, i.e. copy the following URL into your browser's location bar:

   https://fonts.googleapis.com/css?family=Material+Icons+Outlined
   

   This will return a page which looks like this (at least in Firefox 70.0.1 at the time of writing this):

   /* fallback */
   @font-face {
     font-family: 'Material Icons Outlined';
     font-style: normal;
     font-weight: 400;
     src: url(https://fonts.gstatic.com/s/materialiconsoutlined/v14/gok-H7zzDkdnRel8-DQ6KAXJ69wP1tGnf4ZGhUce.woff2) format('woff2');
   }
   
   .material-icons-outlined {
     font-family: 'Material Icons Outlined';
     font-weight: normal;
     font-style: normal;
     font-size: 24px;
     line-height: 1;
     letter-spacing: normal;
     text-transform: none;
     display: inline-block;
     white-space: nowrap;
     word-wrap: normal;
     direction: ltr;
     -moz-font-feature-settings: 'liga';
     -moz-osx-font-smoothing: grayscale;
   }
   

2. Find the line starting with src: in the above code, and let your browser fetch the URL contained in that line, i.e. copy the following URL into your browser's location bar:

   https://fonts.gstatic.com/s/materialiconsoutlined/v14/gok-H7zzDkdnRel8-DQ6KAXJ69wP1tGnf4ZGhUce.woff2
   

   Now the browser will download that .woff2 file and offer to save it locally (at least, Firefox did).

Two final remarks:

Of course, you can download the other variants of that font using the same method. In the first step, just replace the character sequence Outlined in the URL by the character sequences Round (yes, really, although here it's called "Rounded" in the left navigation menu), Sharp or Two+Tone, respectively. The result page will look nearly the same each time, but the URL in the src: line of course is different for each variant.

Finally, in step 1, you even can use that URL:

https://fonts.googleapis.com/css?family=Material+Icons|Material+Icons+Outlined|Material+Icons+Two+Tone|Material+Icons+Round|Material+Icons+Sharp

This will return the CSS for all variants in one page, which then contains five src: lines, each one with another URL designating where the respective font is located.