Truncate

.css-truncate will shorten text with an ellipsis. The maximum width of the truncated text can be changed by overriding the max-width of .css-truncate-target. Unless the full text is so long that it affects performace, always add title to the truncated element so the full text can still be seen.

really-long-branch-name
<span class="branch-ref css-truncate css-truncate-target" title="really-long-branch-name">
  really-long-branch-name
</span>

You can reveal the entire string on hover with the addition of .expandable.

<span class="css-truncate expandable">
  <span class="branch-ref css-truncate-target">this-is-a-really-long-branch-name</span>
</span>