A little known feature of many websites is what is known as a PWA or progressive web app. Basically what it means for you, the hexbear app desirer, is that on a mobile device, some web browsers will let you install the website as an app which will act like pretty much any other app. To do this, open up to any hexbear page and click on the menu. In Firefox there are three dots in the bottom right. You should see an option that says "install." Clicking that will basically allow you to view the website as an app, allegedly with better battery performance.
some browsers will have a button for "add to home screen" but it's just a shortcut to a browser tab instead of a webapp (main differences is that it still opens the whole browser along with it)
Yeah, Firefox has the same option with the same wording if the website doesn't support it.