Why would I want to customize a breadcrumb?
By default, the Drupal Web CMS creates a breadcrumb trail for every page and populates the end of the trail with a page's full title.
These long, descriptive page titles are helpful for supplying detailed information for search engines, or for viewers who land there. But they can look wordy in a breadcrumb, which is meant to be a compact, visual locator.
Example of a long breadcrumb: