When I tested the extension in Firefox, it did not work as per expectations. After trying multiple things like removing comments, renaming some functions and going through the files multiple times, I did not have a clue on the reason for failure.
During my update, I had added a few functions after the original ‘last’ function, but forgot to remove the comma. To add to that, I had added a comma to the new ‘last’ function.
On making the changes, the extension started working.