Are you sure about this? I thought libertarians were against all institutions such as the state with power over people.
UBI is a socialist policy. It seems in total contradiction with libertarian principles to me. How is that possible?
With UBI everyone gets an automatic safety net and the ideal is that if all markets were free of government intervention people would buy what they want, and competition would down the costs of healthcare / education / food etc. So that those with UBI can have the basic necessities of life, without the government needing to do anything (other than dealing with tragedy of the commons type problems.)