Mocha allows you to put before and after blocks outside describe blocks, which makes them run globally. This means that the app server is started before the tests are run, then shutdown at the end. This makes it easier to write UI tests without having to worry about starting and stopping the server in each test.
It's confusing and masks the real problem, which is that the homepage doesn't have proper signposting to documentation and help. Hopefully by removing the redirect we can see what the real problem with the homepage is(/was?) and fix that instead.