Merkuro Flatpak confusion

Hello,

I wanted to try out Merkuro Contacts. I’m running Gnome on Ubuntu, so I’m looking for a Flatpak to keep KDE & Qt isolated. The GitLab readme says:

Merkuro is part of the org.kde.kontact flatpak.

So I installed Kontact from Flathub, but it is only Kontact, not Merkuro.

Is Merkuro really in that Flatpak? How can I open it? Is the readme wrong?

Thanks,
Dan