Good question! I've been active in the Monero community for years, and I don't know how funding requests are approved. Originally, the idea was that discussion on the forum would show whether users are interested in donating, but nobody uses the forum anymore, except for requesting funding.

There is no formal procedure in place. The point is not to accept/reject ideas after a specific procedure, but rather discuss and refine them until they are defined to a point that a proposal can be written.

In my opinion, it is initially up to the proposer(s) to organize and push discussions around their ideas, hence we do not want to impose any specific procedure that everyone would have to follow.