I've updated the outdated number in this line (and removed the section about the drop shadow that no longer appears). Thanks for pointing that out!
However, as you pointed out in the comments – and I agreed – it didn't really make sense for this to be on a privilege-specific page anymore, since it was made available to everyone in 2020 (rather than being limited to those with the established user privilege, as it was when the feature was originally added back in 2011).
As such, I actually ended up removing the info about expanded user cards from the create posts privilege page, and creating a new Help Center page specifically about this feature: How does the User Card popup work?
If there are any links out there (e.g. in FAQs) that currently point to the old page for more info about this feature, please update them as necessary. Thanks again!