Firefox OS Simulator 4.0 released
hacks.mozilla.org
hacks.mozilla.org
Are these apps installed on my phone? Are these even apps? WTF is this?
Firefox OS has an "add to home screen" feature in the browser that creates very similar app icons (there's a very similar iPhone feature - this was the original supported way to provide apps on that platform in fact, before people started demanding an SDK to make apps more like Apple's). It is very similar to a bookmark, in fact it's right under "Bookmark" when the press the star in the browser.
Both of the above types of "apps" just launch a lightweight chromeless browser (there's a little arrow on the bottom of the screen you can hit to get a little toolbar with back/forward/reload buttons).
However they don't have the same access to APIs that a packaged Open Web App (https://developer.mozilla.org/en-US/docs/Web/Apps and https://wiki.mozilla.org/WebAPI) that you'd install from e.g. the Firefox Marketplace could have, since they need to be reviewed and versioned (they are actually downloaded and installed on the phone - https://developer.mozilla.org/en-US/docs/Mozilla/Firefox_OS/...)
embedded into the OS.