IOTL, SVES was a short-lived Saturday night action block that ran on Cartoon Network from March 1st, 2003 until April 10th, 2004. It was CN's experiment with airing Saturday night primetime action premieres after the success of 2002's Adult Swim Action(AcTN) launch and the fact they quite literally started it with reruns of Samurai Jack, Justice League, Transformers: Armada and He-Man and the Masters of the Universe.
The block was successful, so that, and the fact they didn't want older audiences watching the network during the day anymore, is why they moved Toonami to Saturday nights and then eventually canned altogether only to be brought back on Adult Swim by 2012.
Here is a video and a article about it:
Saturday Video Entertainment System, often shortened to SVES, is a 7-hour (7:00 PM - 2:00 AM) action-animation programming block that premiered on Cartoon Network on Saturday, March 1, 2003. The block featured former Toonami programming as well as other animated action series that didn't "fit"...
toonami.fandom.com
And just for fun, the TV Tropes page for it:
The Saturday Video Entertainment System (SVES) was a block of action animation (both Anime and Western) on Cartoon Network similar to another block currently airing at the time. The block aired on Saturday nights from March 2003 to April 2004. It …
tvtropes.org
The block was for all ages, hence why you'd see Pikachu, Yugi, Jackie Chan, He-Man, The Transformers, the Teen Titans and other characters like those in the earlier hours while the stuff people actually cared about like the Justice League, Gundam, Zoids, the Z Fighters and the like later at night for older audiences.
Kinda a shame they didn't at least air The Big O and Inuyasha, nor picked up something interesting like Angelic Layer, Dai-Guard and other stuff just for the block(and later Toonami) IOTL.....
SVES was replaced with Toonami, while Toonami itself was replaced with Miguzi.