ID and Source Microswitch

The microswitch in the image below does not work.
What, exactly, is this type of diminutive switch called? Where might one source such?

It is called a "tactile switch" because it has a noticeable click or feedback as you press it.
You'll need the Height from board to top of button (nearest 0.1mm if possible), and distance between centers of the mounting holes. Also, the with of the sides helps narrow down the thousands available.

Check Digikey.com and search "tactile switch" without quotes.

It should be a 6mm × 6mm tactile switch. They are all a common footprint.

Farnell stock them. This is another possible source on ebay.

Les.

Welcome.
Many flavors ----> https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=tact+switch&_sacat=0
and abundantly available disemboweling defunct electronics. Front panels behind key buttons are good donors.