Installing add-ons
An add-on is a module, a store or a theme someone else made. Settings installs them from Universe’s index.
From Settings
Section titled “From Settings”Get more…, at the end of Settings › Features, Stores and Appearance, opens the Add-ons menu. Each row shows the add-on’s version and size, Installed, Update with the new version, or Needs another Universe when this version of Universe can’t run it.
Pick an add-on to install it, or, once installed, to update or Remove it. Installing turns nothing on: turn a module on in Features and a store in Stores, and pick a theme in Appearance (Themes).
Updates
Section titled “Updates”Nothing updates an add-on by itself: update it from the Add-ons menu. After you update Universe, an add-on that doesn’t accept the new version reads Unavailable, and System check says to update it or turn it off.
Updating or removing an add-on is refused while a game runs: do it once you’ve quit the game.
From a terminal
Section titled “From a terminal”universe extension install also takes an add-on’s URL, an archive or a folder. Settings lists such an add-on as Unlisted, and can only remove it.
To write your own, see Extensions.