It is somewhat of a niche category. I've been on stackoverflow for 9 years and 10 months (at time of writing) so it's taken a while to get here.
Looking at the tags e.g. ADFS:
What's also interesting about this is the other contributors.
Just calling out some of them:
Eugenio Pace and Matias Woloski are the founders of Auth0 and vibronet has recently joined them.
leastprivilege is one of the people behind identityserver.
Across the other tags:
I guess now I need to identify my next achievement!
And onto the next 1,000!