Has zenmap vanished from 20.04?

I've just changed my primary computer from a laptop running XFCE and 19.10 to a desktop running Gnome 3 and 20.04 overall I'm very impressed.

One of the tools I tend to use all the time is Zenmap but I can't locate it in either the software catalogue or via running apt in a terminal window, so I assume it's been removed.

So

1. What's the rationale for this? Are their issues with Zenmap I should be aware of?
2. Is there a simpler way of installing then the way outlined on Nmap's site (i.e. https://nmap.org/book/inst-linux.html )
3. Is there an alternative application that will let me port scan my LAN (IP address / open TCP port is a must-have, description of service and UDP ports are a nice to have since I'm generally just checking if a known port can be seen)

It was removed from the repository due to relying on Python 2 which reached End-of-Life at the start of 2020. You can install Zenmap manually from 19.10 repository:

mkdir -p ~/Downloads/zenmap
cd ~/Downloads/zenmap

wget http://old-releases.ubuntu.com/ubuntu/pool/universe/p/pygtk/python-gtk2_2.24.0-6_amd64.deb
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/n/nmap/zenmap_7.80+dfsg1-1build1_all.deb

sudo apt install ./python-gtk2_2.24.0-6_amd64.deb ./zenmap_7.80+dfsg1-1build1_all.deb

and enjoy.

If one does not want to use manually downloaded deb-packages, then it is possible to use Flatpak version of ZenMap as follows:

sudo apt-get update
sudo apt-get install flatpak

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak install flathub org.nmap.Zenmap

Such installation needs ~330 Mb of downloads, and will use ~1 Gb on disk.

Note: I have filed bug-report launchpad as https://pad.lv/1876269 with packaging request.

The GitHub issue tracker for porting Zenmap to Python 3 can be found here.