TR, TRS, and TRRS plugs are not new, they have been used in the telephone industry for many years, and i'm sure well before that, in fact I have seen a picture of a jack with multiple rings, something like 6 or 8, unfortunately I can't find one on recent searches.
TRS means Tip, Ring, Sleeve, and is the mormal connector for a stereo jack plug, the AV jacks are normally either a separate TRS jack for audio,and a TR jack for video, or can be the TRRS type which combines stereo audio and video.
In this video I show what the development steps were, and why usig a TRRS plug in a TRS socket can mean the output is not where you expect it
This is the diagram that goes with the video, including a couple of combinations that I showed in the video.
As can be seen, for some reason the standards people decided it would be a good idea to move the right channel connection and place the video connection there instead
And mixing different plugs and sockets can lead to damage of equipment, especially if you are plugging into the device's output
A word of warning, I have come across a connector where the ground is on the sleeve, and not on the ring shown in the diagram, as you can imagine, this causes more problems