Notably, the Safe Browsing Update API never sends the URL itself to the server: it does a local lookup with hash prefixes of the URL, and only if that finds some threat does it then send the hash prefix to Google (which gives some degree of deniability, given they never know what actual URL you've visited, and only rarely get anything).

Maybe I just don't want to send Google any info.

Ha! Says Google, right? Anything that gets sent to them is too much.

Says Mozilla, and the source code is available for anyone to double-check. Google doesn't have control over what data Firefox sends to the safe browsing API.

Let me fix that for you: Google doesn't have direct control...

What other items do you think fall into this category?

For instance, disabling geolocation. You need to explicitly approve geolocation requests anyway. If you're sure you'll never ever want to share your location with a site, sure, disable it globally. But recommending this to others as a way to protect their privacy is a bit silly.

Well, I for one appreciate the recommendation and will follow it to get rid of annoying messages. To each their own.