What's the easiest way to copy the current URL in Fluid?
Developer of Fluid here.
Yes, there's a very easy way:
⌘ + L (That's "Command - L")
That will temporarily "show" the toolbar (if it was hidden), and select all the text in the URL location field. From there you can copy it, via ⌘ + C.
Then, to hide the toolbar, you can press:
⎋ esc (That's "Escape")
If the toolbar was previously hidden, this will hide the toolbar.