There’s an updated (March 2021) Power Apps Licensing Guide.
The main change is the inclusion of rights to Power Automate within Windows licences via the Power Automate Desktop product, and there’s a useful table added on page 16 which gives a summary of the Power Automate use rights included in different licences.
Find out more about the Power Automate Desktop product on our blog here: http://bit.ly/30uS0Nc, and download the latest Licensing Guide here: https://bit.ly/3ekVWbE.