This question comes up from time to time.
There's an empty package named Squeak-Version in the image. When you unload a package, let's say Universes-mt.48, you add 49 (48 + 1) to the version number of Squeak-Version and save it as well to ensure that the global Squeak version number keeps increasing.

Levente

On Wed, 25 Nov 2015, karl ramberg wrote:

Universes was removed from menus because it was not functional.

To remove Universes from Trunk one has to take into  account the update number. I think the update number is the sum of all package versions ?

I'm not sure how one does this.

Best,
Karl

On Wed, Nov 25, 2015 at 1:39 PM, H. Hirzel <hannes.hirzel@gmail.com> wrote:
      On 11/25/15, Frank Shearar <frank.shearar@gmail.com> wrote:
      > On 24 November 2015 at 21:09, H. Hirzel <hannes.hirzel@gmail.com> wrote:
      >> On 11/21/15, Chris Muller <asqueaker@gmail.com> wrote:
      >>> On Fri, Nov 20, 2015 at 12:40 PM, tim Rowledge <tim@rowledge.org> wrote:


      >>>> I suggest we should Universes.


      >>> +1.  +1.  +1 and, +1.
      ..

      >
      > I was under the impression that Universes _was removed_, like, back in
      > 4.4 or the beginning of the 4.5 cycle, when I was up to my eyeballs in
      > hairy dependencies... Certainly the build processes think so -
      > https://github.com/squeak-smalltalk/squeak-ci/blob/master/package-load-scripts/Universes.st
      > is the _load script_ for Universes (implying its _unloaded by default_
      > state).
      >
      > frank
      >
      >> I think this has been discussed before the release of 4.6 and people
      >> agreed but at that time it was to late to do it.
      >>
      >> --Hannes
      >>
      >
      >

      Hi Frank

      Indeed I do not see a Universe browser in the app menu of Squeak 5.0.

      However there seem to be some classes left in the system, see screen shot.

      So there was removal but it seems it was not done completely.