VMFXX, the Vanguard Total Stock Market Index Fund Admiral Shares, does not pay dividends. Therefore, the question of whether its dividends are qualified or not is not applicable.
VMFXX is an index fund that tracks the performance of the CRSP US Total Market Index. This index includes a broad range of U.S. stocks, and the fund's returns are generated by the appreciation of these stocks, not by dividend payments.
Instead of receiving dividends, investors in VMFXX benefit from capital gains when they sell their shares. These capital gains are taxed at the long-term capital gains rate if the shares are held for more than one year.
In summary: VMFXX does not pay dividends, so the question of whether they are qualified or not is not relevant.