Usage The new [ST] toolbar button will appear after installation Click on that [ST] button. Ensure all required tabs are loaded - newest Firefox versions do not load them automatically on the start. Reload absent tabs manually if they are absent and required. There will appear window with the text of URLs and page Titles listed there. Then you can edit text there, save, copy the list text into clipboard, etc. Reopen: You can paste there URLs list saved earlier and click [Open...] Saved titles and other non-URLs will be ignored and not opened. Features:

Show URLs with Titles of all tabs of current browser window as plain text.
Save this text into a text file.
Copy this text into clipboard.
Edit the text in place and copy edited version.
Paste new URLs into the text field and open all new URLs at once. URLs currently opened in tabs will be skipped.

Write me in reviews if there will be problems. Please leave positive feedback if you like this Extension, thanks! Later added Note about loading and saving all tabs: "Save Tab URLs" addon saves all loaded tab URLs and Titles, and if you close and open Firefox, the Firefox starting with version 47 [2], will not load all tabs automatically on the start. This is declared Firefox behavior, which done by intention of browser developers to not slow down the whole browser starting process. So the required tabs are need to be manually loaded in case you want to save their URL+Titles. This is browser limitation. This utility addon does not interfere into user relations with his/her browser, allowing that freedom of interaction. In case you need to save all present tabs in any case - Solution exists for that too. This way is to force the browser to load all tabs on the startup[1]. Be informed that this will slow down the overall browser start process. [1] https://support.mozilla.org/en-US/kb/allow-firefox-load-multiple-tabs-background Allow Firefox to load multiple tabs in the background [2] https://superuser.com/questions/1086541/how-do-i-make-firefox-47-load-all-my-tabs-on-startup