Almost as good as pre-FF 57. Only appears to be missing "gather to new tree|folder."

Slightly awkward for dragging of selected tabs -- need to click the menu bar's "select and do" icon to close the context-menu pop-up, then can re-click on selected tabs to move them.

Copy Title & URI doesn't work very well on unloaded tabs yet -- copies the stored data, e.g.
"
Scientists on new supernova: WTF have we been looking at? | Ars Technica
moz-extension://27b1e6ca-d9a9-4fc5-95b7-e4748f3303ca/replaced/replaced.html?state=redirect&title=Scientists%20on%20new%20supernova%3A%20WTF%20have%20we%20been%20looking%20at%3F%20%7C%20Ars%20Technica&url=https%3A//arstechnica.com/science/2017/11/scientists-on-new-supernova-wtf-have-we-been-looking-at/%3Fcomments%3D1%26post%3D34302387&favIconUrl=https%3A//cdn.arstechnica.net/favicon.ico
"
But at least the copy is successful (not blank), and can do a regex transform to clean it up.

Creation of a Tab Group folder (in tree style tab) requires manually going to a moz-extension url, such as:
moz-extension://08da1c1c-1712-42fb-a49a-c0ec608df1f6/resources/group-tab.html?title=%22%20%20NEWS&temporary=false

Hats off to Piro, much respect. Paypal Donation needs to be enabled for Piro's extensions.