At, for example, https://secure.phabricator.com/tag/maniphest/, we get a "quick" list of 10 open tasks in that project. The only suggestion that this might not be a complete list of all open tasks in that project is the tiny "View All" button in the top-right corner.
It needs to be made much clearer that the task list on the project page itself is incomplete. We could use a more accurate term, like "Top tasks".
We have seen that this confuses some new/casual users. This is perhaps not a big deal for new users that will keep using Phabricator, because eventually everybody finds out that there are more tasks. However, we have many casual bug reporters that only visit the site when they have a problem, and these might get a more solid wrong impression. Since the problem can be solved with a simple change of string, it is probably worth fixing it.
Original report: https://phabricator.wikimedia.org/T75698