This is the Npgsql PostgreSQL provider for Entity Framework 6; note that this is the old, non-core version of EF. For the EF Core provider, see https://github.com/npgsql/efcore.pg.
Like non-core Entity Framework 6, this provider is no longer being maintained. It is unlikely that any enhancements or bug fixes will be worked upon, unless they're absolutely critical.