This is always how I did but ubuntu-bug is not part of 23.04:
$ which ubuntu-bug
ubuntu-bug not found
$ sudo apt search ubuntu-bug
Sorting... Done
Full Text Search... Done
reportbug/lunar,lunar,now 11.6.0ubuntu2 all [installed]
reports bugs in the Debian distribution
$
I don't have a local copy of the kinetic manifest, and I can only view Ubuntu Desktop's online now (alas flavors aren't kept normally), but I'd expect it to be there.
I'd check you have apport installed, and if it's not there, install it.
I got that to appear by pressing TABTAB rather than hitting enter after typing apport (the first TAB autocompleted by adding the - and second gave me a list of available commands).
Your install is much older than mine, and those of us who like to tinker, experiment or enjoy our systems often make temporary changes we can forget about.
This install of mine was made using the mantic daily ISO dated 20230829 yet I didn't [then] recall why or when I experimented with au. & main archive which I only noticed in output I used in prior comment; its easy to make a change & forget what prompted our action.