Surprising "grounding circuit" on TAD 6G15 clone

[Lambertini]

Hey all. Can someone explain me the benefits and the concepts behind this surprising "grounding" circuit inserted between the chassis and all circuit ground points in TAD version of the Fender 6G15 tube reverb?

[PRR]

Breaks the ground-loop between reverb and amplifier 3rd-pins. Common in hi-fi. Safe enough and often effective.

[tdvt]

Check out section 15.10

https://www.valvewizard.co.uk/Grounding.pdf

I have used it several times, works well.

[HotBluePlates]

Same issue being discussed about a 6G15 here.