Straight border on rounded box?

I’m not sure what the name of this visual design pattern is, but here are 2 ways to do it using CSS.

With a pseudo-element


.box1:before {
  content: "";
  position: absolute;
  left: -10px;
  top: 0;
  height: 100%;
  width: 10px;
  background: #FF1493;
  border-top-left-radius: 10px;
  border-bottom-left-radius: 10px;
}

With a gradient background


.box2 {
  border-radius: 10px;
  background-image: linear-gradient(
    to right, 
    #00BFFF 10px, 
    white 11px
  );
  padding-left: 35px;
}