A few issues:
1. I just installed this, and the Padlock icon doesn't show up in the spot the screenshot here indicates. Instead there's a little square bit of nothing which I had to guess opens the interface.
2. Not specific to this add-on, but add-on creators evidently LOATH spending 5 or 10 minutes to document their product and explain, step by step, how to use it and where to find the various interfaces. Hint: A screenshot of a disembodied interface with no explanation of where it occurs doesn't cut it.
3. In my test, I applied it to a Forum and I don't see how it does anything but apply a limit to an individual thread.
We'd hoped to be able to apply limits to an entire Forum. Applying the limits thread by thread, on a busy site, would be too much of a pain in the ass. If there's a way to do what we hoped, I don't see it in the screenshots and found no written documentation otherwise. I'd love to find out it actually does that and how to apply it.