The tax foreclosures generally wipe out all liens against the real estate, IRS, mortgages, mechanics liens etc. Those entities can pay the taxes if they want to preserve their lien but when they don’t pay the taxes their lien is lost in the majority of the cases.
If they do “show up” to get paid, we have a special technique to make them prove that the lien is valid (hint, they can’t find the documents and our background in law and loan modifications/challenges gives us tools to use to challenge the lienholder to PROVE they have a valid claim).