To me an explicit safe space for LGBTQ kids is not necessarily a separate meeting ground. Rather, all spaces should be explicitly safe for LGBTQ kids.
Explicitly safe is different from a general safe space in that many people could take a training, put a sticker on the door, and be a passively “safe space.” In an explicitly safe space the person at the head of the room not only actively stands up against anti-LGBTQ sentiments and bullying, but proactively includes those students or families in representation and discussion. They offer a structure that includes LGBTQ students rather than just defending them. (That is not to say anything negative, of course, about the traditional Safe Space based on anti-bullying, acceptance, and a ready ear.)
So, I think that explicit is more about being proactive and including LGBTQ students among everyone else, in every sense of the word, not about creating a separate space specifically.