If you need to email everyone on a project, it’s probably no big deal to find people’s account information and cut and paste into an email. But if you have hundreds of users on a project, just go to the database and get their emails. First find the project id, then get all the emails for people on that project.

mysql> select users.mail from members left join users on members.user_id = users.id where members.project_id = 14;