Click on the button Open next to the section "Open logs directory (cb.log)". This opens the directory where the Cosmos Browser log (cb.log) is stored.
By default, this is located in (for Windows): C:\Program Files\Common Files\ChaosGroupChaos\ChaosCosmosCosmos For macOS: /Library/ChaosGroupChaos/ChaosCosmosCosmos/cb.log