Undocumented retainer heap profile SYSTEM entry
Summary
Heap retainer profiling can generate entries named "SYSTEM", which are not described anywhere in GHC's user guide AFAICT.
Proposed improvements or changes
Describe what the SYSTEM entry means. Also, it would be helpful to describe if possible what can be the cause of excessive SYSTEM memory usage, if that is not made obvious by the description of the thing in itself.
Environment
ghc 8.10.2