For anyone who's wondering, Firefox handles Safe Browsing a lot differently. There's an overview here: https://feeding.cloud.geek.nz/posts/how-safe-browsing-works-... It's possible that this is outdated though.

The tl;dr is that

1. Firefox downloads a list of partial hashes every 30 minutes from Google. It's only the first 32 bits of each hash. This can easily be turned off in about:preferences.

2. When you visit a website, Firefox checks the beginning of the URL against the partial hashes stored locally.

3. If the partial hash matches the beginning of the URL, Firefox downloads a list of all of the hashes beginning with the partial hash it matched.

4. Firefox checks the full hash of the URL against the new list of full hashes. If it matches, the site is blocked. If not, you continue on browsing.

When I first found out how it worked a while ago, I was pretty amazed. It goes to great lengths to not know what sites you're visiting.