@FrogReaver
I've explained to you what the mechanism is: A makes an offer to B, which B accepts, and as a result B enjoys a licence in respect of W's property.
Section 4 uses the verb "grant" in relation to the contributors. To me that seems mostly a drafting convenience, as it covers both multiple parallel contributors as well as contributors at different places in the "stream": eg W licences to A and B, then C publishes a work that draws on both A's and B's material - the licence terms require C to include only one copy of the OGL, that names W and A and B in its section 15; and so both A and B are unmediated contributors, whereas W's contribution is mediated via A and B.
Characterising the grant as flowing from all those contributors makes the drafting straightforward, and does not cause any problems given that all the licences are on exactly the same terms and govern exactly the same content.
Why is it important to you to label one of A or W the grantor? What legal consequence are you trying to establish or investigate?