1) There was an update to the UrzaGatherer android-app a couple days ago which seems to have changed the app from a "standalone app" to a "web app", apparently using the device's default-browser to serve the website.
2) In one sense this is good, because I think it means the dev can save time by not having to push frequent updates to the app through the Play Store.
3) However, it has the negative side-effect of causing an address-bar to appear at the top of the screen, which cuts away from the already small amount of screen real-estate.
4) I tried 18 browsers in total, searching for ones that lets you add UrzaGatherer as a web-app through its "Add to homescreen" function, without causing that address-bar to show up. Of those 18, I found three that let you add a homescreen-shortcut/"app" for the site without showing that address-bar. (there's possibly a couple others which were missed due to complication I discovered later [see below], but 'tis fine)
Of those three browsers, there are two "types":
1) A browser which lets you add "homescreen shortcuts" to websites, but ONLY if you run the "add to homescreen" function prior to the website's "notifying the browser of its associated app" -- after that point, the browser will replace "add to homescreen" with an "install app" function (which is not what we want since that adds the address-bar). So for these sites, you need to clear the cookies/site-data (if already loaded), refresh the page, then "add to homescreen" before the site can supply its "install app" information.
2) A browser which lets you add "homescreen shortcuts" at any point, even after the site has supplied its associated "install app" information.
For type 1, there are two options: Chrome, Vivaldi
For type 2, there is one option: Aloha
Type 2 is preferred of course, but Aloha has two drawbacks:
1) It's not a mainstream browser (so you might not want to install it).
2) It pops up a small elipsis-icon on shortcut open, lasting a few seconds (or until swiped down).