When I visit a url like https://phabricator.khanacademy.org/project/view/45/ on my web browser, there's icons on the side to do things like add members to the project. But when I visit the same url on my phone, there's no side-icons, and no way (that I can tell) to add new members.
It would be nice if I could add members to projects from my phone!
I assume workboard, feed, and open tasks are likewise inaccessible, though I don't use those features so I can't say for sure.