Some HTTP certificates do exactly that, and web browsers used to show the company/identity the certificate was issued to in the URL bar. Now you have to go to the certificates detail, very clear on Firefox, behind a few clicks on Chrome. Here's an example from a bank in Spain: https://www.bbva.es
The current version is 0.0.13 (on the homepage), it's normal that the author is focusing on their platform at the moment. It probably was too son to post it on here.
Not the OP but I use all the programs full screen / maximized. I change windows with alt+tab or maybe I reach down to the dock to select the app icon quicker. I only see my wallpaper when changing workspaces, because the animation shows it a split second. I do use the command line but it's not the only way to not show the wallpaper. This is true whether I'm on Linux or macOS.