Your manual dialed in saturation.
The versatile compressor by Audio Teknikk
A saturation plugin by GVST.
Is it a multiband compressor? Is it a dynamic EQ?
The ThrillseekerVBL is an emulation of a vintage broadcast limiter, offering compression up to limiting and a saturation based on tube and transformer saturation.
TesslaSE is an easy to use saturation plugin.