It is specifically targeted at folks who are not purely a binary gender (arguably by definition not cis, but I'm not going to enforce labels on anyone). Their preface/definition can be found below:

Who can take part?

The gender binary is a societal model that classifies all humans into one of two categories:

Woman/girl – always, solely and completely
Man/boy – always, solely and completely

If you feel like that doesn’t fit your experience of yourself and your own gender in some way, you are invited to participate. This includes, but is definitely not limited to:

people whose genders change over time
people whose genders fluctuate in intensity
people who experience more than one gender at a time
people who don’t experience gender at all
people whose gender is neither male/man nor female/woman

We also welcome anyone who:

rejects gender altogether
feels like they’re outside of gender
feels like they transcend or move beyond gender or the gender binary
doesn’t really understand gender as it applies to them
is questioning whether their flavour of trans might be binary or nonbinary

It’s completely up to you whether you feel you fit any of these. This survey leans on the side of inclusive.