.tab-bar {
    display: grid;
    grid-auto-flow: column;    
    column-gap: 5px;
    margin:10px
}

.tab-bar>div {
  border:1px solid red;
  text-align:center;
  padding: 5px;
}

.tab-bar.bar1 { }

.tab-bar.bar2 {
  grid-auto-columns: max-content;
}

.tab-bar.bar3 {
  grid-auto-columns: max-content;
  justify-content:center;
}

<div class="tab-bar bar1">
<div>Alice</div>
<div>Bob</div>
<div>C</div>
<div>D</div>
<div>E</div>
<div>F</div>
</div>

<div class="tab-bar bar2">
<div>Alice</div>
<div>Bob</div>
<div>C</div>
<div>D</div>
<div>E</div>
<div>F</div>
</div>

<div class="tab-bar bar3">
<div>Alice</div>
<div>Bob</div>
<div>C</div>
<div>D</div>
<div>E</div>
<div>F</div>
</div>