The Zfnd only has some limited authority: a software repo, its funding, engineering staff, in the future a position in a trademark agreement. So, “Veto” only has meaning in that context. For example, by only contributing engineering effort to a software branch that doesn’t make mandatory funding to a for-profit.
The community ultimately decides by choosing what software to run, etc. The Foundation has also committed to incorporating public feedback into our own decision making. It’s advisory in the sense that our bylaws say the root authority of the Foundation is the majority vote of board members. Public votes/feedback are useful to the community even beyond guiding the Foundation’s decision - if you had to fire the Foundation for example by moving to a fork we didn’t support or something, the public feedback could help catalyze that.
This is all my best attempt at explaining what “veto” and “foundation governance” means. It’s consistent with everything the foundation has written so far. Hope it helps!