I don’t know if I can give a straight answer. Agencies and their divisions, orgs, branches, teams have to do records management. There’s a federal law somewhere in the federal registrar. So a certain amount of historical knowledge is preserved. Where, how well, and how far back is a bunch of rabbits holes.
But what I think you might be getting at is tribal knowledge. Everything that’s passed around orally or by experience rather than being written down. There’s always that risk with people leaving and that knowledge going with them. But that impact can vary depending on agency practices, work culture, or even just the responsibilities of the person leaving.
The area I’m keeping an eye on are the people with decades of knowledge and experience that are also skilled enough to apply all that to their niche fields within an agency. They’re usually the ones in federal service for the long haul and are some of the more difficult people to get time with. If an agency is gutted and that living knowledge base is lost then the agency will struggle to fulfill the missions Congress has directed they must do as federal law.
Congress hasn’t passed a budget yet for the fiscal year, only a continuing resolution. The fiscal year started on Oct 1. So, Congress could include language that legalizes the buyout in the full budget, in theory*. There’s going to continue to be lawsuits against it before and after the budget becomes law. So, who knows what will happen in practice.
In any case, my take is anyone that took it will find that it won’t work out like they hoped. At a minimum they will have a stressful couple of months. At a maximum they will find that they screwed themselves.
*IANAL so apply appropriate skepticism to my Thursday evening quarterbacking.