You can no longer add your current text to an ongoing "list" of saved text in a single lengthening document, you just get "(1)" to "(109)" in your (109) tiny titles. You can ask for and receive a dialog box pop-up to choose where to save you file BUT you can't set anything but the default "Downloads" as your own "default." Such a my folder in Downloads called Text-to-File Web Docs folder.
I give version 2.73 SIX stars and use it on my older computers with love and abandon. But for my needs I have to give all the versions since 2.73 (Firefox 57+) a very frustrating zero.
If it gets its old power back I will re-review in glowing terms, but right now it's just frustrating to open dozens (109 files today) to combine them by hand for web research on a particular topic. EXTRA: Now it doesn't even change the titles (109) to (110) for you to save; you have to rename each file by hand.

[made as an addendum on 8-16-2018, 6:00 PM EDT: Avalon27703]

Mr. Byrne,
Thank you so much for taking the time to tell me exactly where the problems between your Add-On and the new and "improved" Firefox releases reside. I have had similar experiences with several other of my favorite and most useful Add-Ons. I'm sorry Firefox/Mozilla is giving you (and so many of us) so much trouble and though I wish you could make Save Text To File glorious again I understand why it would just be a lot of trouble. And it makes me sad.
For my part I may have a work-around (I haven't looked at the dangers yet) to be able to use 2.73 on my computers with newer OS's. For times when I'm specifically doing dedicated subject research where your work is so helpful I'm just going to reinstall a pre-FF-57 browser and work from there. If your Add-On is as important to others as it is to me perhaps my idea will resonate with some other users. Or maybe when I try I will accidentally have both browsers running at the same time on my computer and smoke will start to fill the room.
I am grateful for your great works! And again for anyone reading, I give version 2.73 a solid SIX stars out of five.
Thank you for giving me so much of your time,
Robert (Avalon27703)

Compared to the pre-57 Firefox version, this one sucks.

I used this add-on before F. 57.0 and gave it 5-stars. I was waiting for a version for Firefox 57. I'm glad Save-Text-to-File 3.1 finally arrived. I do use it daily.

However, I'm disappointed in this release. Simple, but valuable features have been left out. Most importantly, you can't designate a your own default directory for the text files. Instead, they all go into the download directory by default. I could only change the directory for the current message, not for all. Why?

Moreover, you can't tell it to append text to an existing file. STtF 3.1 also isn't intelligent enough to put a number on successive text files made on the same day from the same site.

The app had all of these features before. They would seem simple enough, why have they disappeared?

I was disappointed enough to be tempted to give this two stars, but that implies I don't use this add-on. In fact, even with its missing features, I still do. It has 50% of what I need and I can work around the rest.

It's just functional enough to be useful.

Good, but now you can't save from many sites, e.g. IMDb :\ And in the reader view, nothing ... | NEW(s)!!! : It works again! I only installed Waterfox because it hasn't worked so far. Ctrl + Shift + Y ! Thank you for your work.
OLDER: I used to write this:
There's only an older version (2.7.3) of it running with Waterfox :@
Unfortunately there is no change :
Now: "Error occured" (version: 3.2.4 / 2018.12.31.) :@
That was my favorite addition. <3
I was looking forward to updating but I did not know it was ready for the new Firefox. What I tried (today, January 18) is no longer working with 57.x: (((
I'm looking forward to the fix and the 5 stars!
Suggestion: not just a right mouse button but also a keyboard combination (shortcut) save (like the old times)