UPDATE: (Jan. 20, 2018) I received a warning from my AVAST malware anti-virus that said this add-on (Multiple Past and Go Button) may track everything you do online. It may be a false positive, but perhaps the author can comment. (The plugin should only have access to the URL's you paste from your clipboard. That's what may be considered "tracking" by Avast, in which case it is not an issue. However, if the author transmits your data over the internet, or keeps your data in his private database, then that is an issue and a violation of privacy.)
As of Nov. 2017, v57 (Quantum), existing Firefox addons can EITHER copy OR paste, not both ( Until someone develops an addon that can do both). Thus we must find a replacement for Copy URLs Expert, or Copy All URLs.
SOME ALTERNATIVES Here is what is working for me, now...
(1) Copy All Tab Urls WE (Web Extension) by Michele Pezza https://addons.mozilla.org/en-US/firefox/addon/copy-all-tab-urls-we > This only copies URL's
Combined with... PASTE URL's
(2) Open Multiple URL's by tp12 https://addons.mozilla.org/en-US/firefox/addon/open-multiple-urls/