Is the validator still maintained at all?

Hi, there!

I just discovered that the validator fails on some markup and CSS that 
should be valid according to MDN, so I thought I might report an issue. 
On the GitHub project page I noticed that the last release of the 
validator is four years old and one of the issues I found (use of 
<search> element anywhere in a document raises an error) was reported 
one year ago but was not fixed since.

So I wonder, if the validator has been abandoned and is unmaintained?

Thank you and best greetings from Germany

Holger Löwenherz