Did you look at the holdings of VEXMX - Vanguard Extended Market Index Fund Investor Shares1. No (not as of yesterday, according to public information that they update daily themselves)
It was revealed here in the past day that they hold ~$9,5B of TSLA and the charter for this ETF requires them to sell any stock that appears on the S&P 500 Index.
Most likely is that Vanguard will conduct an internal xfer of those shares to their S&P 500 ETF at the Closing SP on Friday, and report this private market transfer (a.k.a. 'Dark Pool') no later than 16:00:04 hrs on Fri, Dec 18, 2020.
Then those shares of TSLA will appear on the other ETF in the next daily reporting cycle.
It's unknown if other large funds have similar arrangements, but that speaks to our knowledge gap, not the mechanism of providing liquidity.