The latest commit introduce the service worker and a manifest for web app.
The advantage to use a web app is for the smartphone and improve the speed of the website.
If you want more information about that, just follow these links :
about the web app : https://developers.google.com/web/fundamentals/web-app-manifest
service worker : https://developers.google.com/web/fundamentals/primers/service-workers
About the manifest, you nothing to do but if you want change the logo, you must go in this directory /sources/images/logos/manifest
just replace the logo by yours and you must respect also the size of the image.
Do not change the name of the logo.
I hope this information will be useful for you.