Hi Jakub! Thanks for your comments :) You are right that kanban does not provide estimations or commitments — when something is done it is done. This was an experiment combining some Scrum and Kanban practices. Within the team there was uncertainty if the tasks would be done in the shortest time possible and not be prolonged “indefinitely” thus introducing the estimation element. This was not set in stone but rather a rough reflection on the time & effort involved.
Today I am not sure if this was a good idea. I think that might have hindered trust within the team, their self-organization and part of the responsibility for contacting with the stakeholders.