apt - Where can I obtain a list of all virtual packages provided by a Ubuntu distribution / release (e.g. bionic)?

1. At https://packages.ubuntu.com/, we follow the link "bionic" under "Browse through the lists of packages:".


2. At https://packages.ubuntu.com/bionic/, we follow the link "Virtual packages".


3. We reach https://packages.ubuntu.com/bionic/virtual/, but nothing is shown there (I think this is a bug!).

If we know the name of the virtual package (e.g. build-essential), we can display the information by manually typing the full URL, like the following:

This bothered me for 10+ years (since perhaps Ubuntu 6.06 or 8.04). Does anyone know where I can obtain a list of all virtual packages?

Thanks!

The aptitude package manager's search function can match virtual packages as follows:

aptitude search '?virtual'

However build-essential isn't such a package - in Debian terminology, a virtual package is described as follows:

A virtual package is a generic name that applies to any one of a group
of packages, all of which provide similar basic functionality. For
example, both the konqueror and firefox-esr programs are web browsers,
and should therefore satisfy any dependency of a program that requires
a web browser on a system, in order to work or to be useful. They are
therefore both said to provide the "virtual package" called
www-browser.

So for example the virtual package xserver may be provided by any of

$ aptitude search '?provides(^xserver$)'
p   tigervnc-standalone-server                                              - Standalone virtual network computing server
p   tigervnc-standalone-server:i386                                         - Standalone virtual network computing server
p   tightvncserver                                                          - virtual network computing server software
p   tightvncserver:i386                                                     - virtual network computing server software
p   vnc4server                                                              - Virtual network computing server software
p   vnc4server:i386                                                         - Virtual network computing server software
p   xnest                                                                   - Nested X server
p   xnest:i386                                                              - Nested X server
p   xserver-xephyr                                                          - nested X server
p   xserver-xephyr:i386                                                     - nested X server
p   xserver-xephyr-hwe-18.04                                                - nested X server
p   xserver-xephyr-hwe-18.04:i386                                           - nested X server
i   xserver-xorg                                                            - X.Org X server
p   xserver-xorg:i386                                                       - X.Org X server
p   xserver-xorg-hwe-18.04                                                  - X.Org X server
p   xserver-xorg-hwe-18.04:i386                                             - X.Org X server
p   xvfb                                                                    - Virtual Framebuffer 'fake' X server
p   xvfb:i386                                                               - Virtual Framebuffer 'fake' X server

Unfortunately I don't think there's a specific search term that would let you identify "packages like" build-essential - I've seen it sometimes referred to as a dependency-only package, but that's not strictly true since it does install some files of its own.

References: