Compared to
X tells you when somebody follows you and never tells you when they leave. Your count drops by four and there is no way to learn who.
Muffle opens your followers page and reads the list as your own browser loads it. That snapshot is kept in your browser. The next time you scan, it compares the two and shows you the difference.
The first scan gives you a baseline and no diff, because there is nothing to compare it against yet. The second scan is the one that answers the question.
The difference is structural rather than a feature list. Hosted tools authenticate as you against X's API, which is why they can be capped, priced per account and switched off. Muffle reads a page your browser already fetched.
Leave your email and you hear once, on the day it goes live, while it is still $29$19 a year.
We do not send anything else, and never share this email with anyone else.