Segment markup
Assets are made of segments with translatable text and of segments or attributes with non-translatable markup. By selecting the Show Markup check box in Browser Workbench, you can view the segments with non-translatable markup as well as those with translatable text and attributes.
In the following image, segments 6m, 7m, and 7m001 consist only of markup and are not translatable:

If the markup segment is extremely long, Browser Workbench displays only the beginning and end portions of the markup, with an ellipsis in between.