Mozilla Foundation has large overhead on management (CEO getting more while people getting fired), and it has that structure of a non-profit within a for-profit of the same name/brand.
For organizations providing grants, I don't think Mozilla even does that? Unless you mean stuff which is brought under the umbrella of Mozilla. Even YC and Google provide grants, its just with a twist (not selfless with the kicker being private equity). For an organization which provides selfless grants, there's for example the Dutch NLnet Foundation [1]. Which also falls under a different jurisdiction which can be a pro or con.