How can I export all my open Firefox Tabs to a text file?
On Android system you can use Termux (No root required):  


Navigate in Firefox to URL: file:///data/data/org.mozilla.firefox/files/mozilla/  
Choose the link of ***.default folder of your profile  
Choose the sessionstore.js file  
Copy content of this file and save it in sessionstore.js file on local storage  
Run the command in Termux to output your tabs urls:  

cat ~/storage/shared/sessionstore.js | sed -n 's@{\"url\":\"@&amp;\n@g; s@\",\"title\"@\n@gp' | sed '/^[:{]\"/d'


Or, this command to save your tabs urls in file sessionstore.txt on your local storage: 

cat ~/storage/shared/sessionstore.js | sed -n 's@{\"url\":\"@&amp;\n@g; s@\",\"title\"@\n@gp' | sed '/^[:{]\"/d' &gt; ~/storage/shared/sessionstore.txt