found this a few weeks ago and it seems pretty bullshit for it to not be public knowledge
it sets your lerp to 0.0 ms and hitboxes seem to lag behind the player models (by i assume a tick?).
very useful for tracking (especially air headshots) because you dont necessarily have to predict where someones gonna move you can just follow behind them. artificially improves your reaction times for tight angles and lets you get some bullshit shots round corners
cl_cmdrate 100
rate 10000000
cl_updaterate 10000000
is the full thing but i'm pretty sure the only thing that matters is the ridiculously high update rate (which somehow isnt limited by sv_maxupdaterate 66 in the ETF2L config)
i was gonna get on a server and test it out with OBS recording but i'm too lazy
seems to increase your ping by around 10ms so its not worth using for projectiles imo