todo.horse is a web-based hierarchical text editor (similar to Org Mode). You can visit it at http://todo.horse/ .
todo.horse hosts its own tutorial and changelog so everything you need to know, you can find in the todo.horse itself.
If you want to ask a question or submit a bug, use the GitHub issue tacking system.
To run local instance of todo.horse, execute python -m http.server 8000.
If you have some data, stored on Clearly.pl, you can import it to todo.horse by running the following code in the browser console (hit F12 or Ctrl+Shift+C when on clearly.pl, paste it into the Console tab and hit Enter):
var f = document.createElement('iframe');
f.src = 'https://todo.horse';
f.style.display = 'none';
f.onload = function () {
f.contentWindow.postMessage({
type: "import",
json: JSON.stringify(localStorage),
}, '*');
};
document.body.appendChild(f);