This has the potential to be great add-on, but there are two glaring bugs:

1. The option to show warnings would should save the file without confirmation. It is incredibly annoying having to wait for the dialog book to show up in order to save the file! Note that I do want to see the warnings about resources not saved; however, I don't want to be "held hostage" by the need to confirm the save. I tried both "Show warning if any resources cannot be saved" and "Show list of all resources that cannot be saved", and neither does the trick

By the way, how do I send a donation? Implementing a third option like "After saving, show warning if any resources cannot be saved" is a no-brainer!

2. It doesn't allow the ability to save settings across machines via Firefox sync. This is incredibly annoying, because I use many different machines and VM's. If you can't implement readily, please point out a workaround. That would be another donation worthy fix.

I thought this might be a Firefox limitation, but I ran across the following Reddit comment suggesting otherwise when trying to find a workaround myself:
Firefox provides a way for addons to sync data: https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/storage/sync but it's up to developers to choose what they sync and what they keep in the local storage.
[via https://www.reddit.com/r/firefox/comments/7e8l8p/firefox_doesnt_sync_addon_settings]

Please make an attempt to fix them or offer good workarounds, so I can give you a 5-star review (It was a 4-star review, but I later remembered about point 2.) You might also try requesting that Firefox fine-tune its rating system, so I could have given something like 3.75.

Another annoying quirk is that there is no way to specify that the "saved" status be made permanent. This can be done stylishly by changing the "SAVE" to a light gray at the very end. A better way would be to omit the "SAVE", and just change the color of the icon gradually from dark blue to dark grey during the progress of the save operation. (This might be confused with the page-not-ready-for-saving color, but that color could be changed to a slightly brighter shade of light blue.)

If that were added, I can bring the review score back to a 4.