Yep, I've been getting these emails since 2014, around 200 in total. My extension has had between 30,000 and 100,000 active users. They often quote up to $500 a month per 1000 users, which sounds too good to be true.
It often missed what should have been exact matches. You could copy and paste a variable name or a string from the repo and the search would not find it.
You can deny push notifications by default in your browser settings and never be prompted again. They can still be manually allowed on the sites where you actually want them. Same goes for location requests and other "site settings".
Aside, I've been waiting years for a favicon API, which Chrome has had from the start. It's a pretty glaring hole for any extension that displays bookmarks or history.
The Decentraleyes[1] and LocalCDN[2] extensions aim to do this in part. But the effectiveness is limited since they only have a handful of libraries and most sites bundle their javascript.
You can also adjust density, rounded corners, transparency, blur, etc.