It doesn’t exist, and some people get really mad whenever someone tries to make one.

https://cathode.church/fedi-scraper-counter.html

Seems to me the solution to this is registering protocol handlers for URLs, which Mastodon tried and gave up on because they weren’t happy with how web browsers handled it.

There’s a small, but extremely loud segment of the Mastodon userbase that seems to view presenting public posts in any manner that’s different from how a vanilla Mastodon server does as an invasion of their privacy. There have also been a few projects that raised reasonable concerns about privacy and moderation, but this page doesn’t seem to make a distinction.

It appears to contain misinformation about FediFirehose, which ran client side and just showed the output of a public relay.