How to install package with Nginx (debian Jessie)

Steps to reproduce on Jessie:

[add aegir debian repo as in http://aegirproject.org]
apt-get install nginx
apt-get install aegir3

This tells me that it wants to install apache2 but I already have nginx.

Here are the dependencies on aegir3-hostmaster :
Depends: debconf (>= 0.5) | debconf-2.0, drush (>= 5.5), php5-mysql, apache2 | nginx, libapache2-mod-php5 | php5-fpm, aegir2-provision (>= 2.4), git-core, unzip, lsb-base (>= 3.0-6)

I admit that I'm a little out of my element, but shouldn't nginx have only php5-fpm as a co-requirement (as per the docs)? Unless I misunderstand this, you can only depend on nginx if you have apache2, which seems counter-intuitive. (libapache2-mod-php5 depends on apache2.)

As far as the docs go, we only need one web server or the other, so we should change the docs if this is not the case (although I couldn't fathom why).

I might try to write a patch if anyone can confirm this is an issue and not just me missing something.