Installed Java SDK:

sudo apt update
sudo apt install default-jdk
javac --version

javac 11.0.9.1

Cloned the repository:

git clone https://github.com/tronprotocol/wallet-cli

And found the following in wallet-cli\src\main\resources\config.conf:

First, as a true C++ developer, I installed Ubuntu 18.04 and compiled omnicore from sources, but after that I realized that Windows omnicore-0.9.0 client can be downloaded and run directly on my Windows 10 machine.

I found omnicore-qt.exe in the unpacked files and run it: