gender identity it tends to be talking about people's personality traits, preferences, skills, behaviours etc.
It means that in some contexts, but in the context of trans people it means (from the interim cass report) “a personal internal perception of oneself”, which isn’t the same thing. I don’t know why people on here mix this up so much. Gender identity, in the sense the cass report is talking about, isn’t personality traits, preferences, skills and behaviours.