Why can't I install Tomboy in Ubuntu Mate 19.04?

In a fresh install of Ubuntu Mate 19.04 (64 bit) when I try to install Tomboy this is what I get:

$ sudo apt install tomboy
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package tomboy is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'tomboy' has no installation candidate

sources.list has the Universe repository (as by default), packages.ubuntu.com shows it's not available, and apt-cache search comes back empty and I can't install it.

Is Tomboy completely gone ? Is there another way of geting it in 19.04 ?

I'd appreciate any suggestions on this, I couldn't find previous reports of this problem.

Tomboy has been discontinued in Ubuntu 19.04 and later, however Gnote is almost identical to Tomboy and in fact you can export Tomboy notes and then copy all of them together into Gnote. You can also export Gnote notes and then copy all of them together into Tomboy. You can use Gnote as a backup app to store backups of Tomboy notes and vice versa, because Tomboy notes and Gnote notes are completely compatible.

To install Gnote in all currently supported versions of Ubuntu open the terminal and type:

sudo apt install gnote  

As per Tomboy's website, the package tomboy is no longer maintained. A new project was started called tomboy-ng. This package is not available in Ubuntu's repositories, but you can download it from the git-website. The instructions for downloading and installing tomboy-ng are on their website as well.

Please examine your link to packages.ubuntu.com more closely: The TomBoy package is available in Cosmic, but not Disco.

Looking further into the problem:

Tomboy is a gnome application, and can be found at https://wiki.gnome.org/Apps/Tomboy. Following the links to the github, it seems that Tomboy 1.15 is the latest version and has not been updated since 2017. You could download and compile this yourself. I assume that this does not work well, or the Ubuntu developers would have included it in the Disco release.

There is also Tomboy-ng, the current development branch of Tomboy at version 0.21. The github has links for .deb files, and instructions for installation, at https://wiki.gnome.org/Apps/Tomboy/tomboy-ng/DownLoadInstall

I guess the reason for tomboy having been removed from 19.04 is that libgconf2.0-cil is no longer supported. This is quite a hack, but you can download this package and tomboy build for older ubuntu versions and install them (at your own risk).

https://launchpad.net/ubuntu/+source/tomboy/1.15.9-0ubuntu1/+build/13188678 https://packages.ubuntu.com/xenial/all/libgconf2.0-cil/download

wget https://launchpad.net/ubuntu/+source/tomboy/1.15.9-0ubuntu1/+build/13188678/+files/tomboy_1.15.9-0ubuntu1_amd64.deb

wget http://mirrors.kernel.org/ubuntu/pool/universe/g/gnome-sharp2/libgconf2.0-cil_2.24.2-4_all.deb  

sudo apt install libappindicator0.1-cil libdbus-glib2.0-cil libdbus2.0-cil libglib2.0-cil libgmime2.6-cil libgtk2.0-cil libgtkspell0 libmono-addins-gui0.2-cil libmono-addins0.2-cil libmono-cairo4.0-cil libmono-posix4.0-cil mono-runtime

sudo dpkg --install libgconf2.0-cil_2.24.2-4_all.deb
sudo dpkg --install tomboy_1.15.9-0ubuntu1_amd64.deb

I prefer this solution because I still want to sync my notes with my grauphel (Tomboy notes server) on nextcloud. Thinking about switching to carnet, though.