Currently, WatchHotReloadService hardcodes a list of capabilities in it's implementation: https://github.com/dotnet/roslyn/blob/4458d002fe24f68bc66e961d807c7569aa99d9f8/src/Features/Core/Portable/ExternalAccess/Watch/Api/WatchHotReloadService.cs#L31-L32. This needs to be replaced by a value provided by the runtime: https://github.com/dotnet/runtime/blob/main/src/coreclr/System.Private.CoreLib/src/System/Reflection/Metadata/AssemblyExtensions.cs#L85-L88.

• The agent (injected component) can query the runtime and return the value of AssemblyExtensions.GetApplyUpdateCapabilities to watch.
• Watch would have some API to return this result to WatchHotReloadService