Open an action run in a new browser tab
Command-click, Control-click, or middle-click any action run to open it in its own tab, and keep your current view where it is.
Comparing two runs used to mean clicking into one, going back, then clicking into the other. Holding Command and clicking did nothing useful, because the run rows were not real links.
Modifier and middle click
Command-click, Control-click, or middle-click a run and it opens in a new browser tab. Right-click gives you the browser's "Open in new tab" option too. A plain click still opens the run in place, as before.
Every run list
The same behavior works in the three places you see runs: the recent runs on an action card, the run history drawer, and the run list on an action's detail page.
Open a few runs side by side when you want to compare outputs, and keep the list you were browsing intact.