It looks like back painted glass. You need to find a specialty company that does this in your area. They measure your space, cut the glass to size and then etch one side of the glass so it holds the paint. Don’t forget to pick the colour you want considering that regular glass has a green tint to it. There is a crystal clear glass for a premium price. Hold your paint chip behind the glass to show the final colour - adjust accordingly.

Don’t try to imitate the process, it won’t work. I know someone that painted the wall first in their desired colour, but once the glass was laid overtop it magnified the wall’s imperfections. Not a good look.

Thx thx