libgconf-2-4 is not available in Ubuntu 23.10

Running:
```sh
LANG=en sudo apt install ./keybase_amd64.deb
```

…gives the output:

```
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'keybase' instead of './keybase_amd64.deb'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
keybase : Depends: libgconf-2-4 but it is not installable
E: Unable to correct problems, you have held broken packages.
```

I'm running Ubuntu 23.10. I've run `apt update && apt upgrade`. I've also enabled universe (as was suggested somewhere) using `add-apt-repository universe`. But it seems that libgconf-2-4 is just not available in Ubuntu 23.10.

According to `control/control` in the deb file, the version I'm trying to install is: `6.2.3-20231016183016.06cb935ee3`

Start by reproducing the reported `apt install ./keybase_amd64.deb` failure on Ubuntu 23.10 and inspect `control/control` in the 6.2.3 package for its dependency declaration. Compare the dependency with packages available in Ubuntu 23.10; done means the Keybase package can be installed without requiring unavailable `libgconf-2-4`.

Written by the indexing model from the issue text.