Select the comment, the details are shown in the Breadcrumb information at the top of the Comment cell, and reports Business Units > Accounts > Periods in a Business Unit View, or Accounts > Business Units > Periods in an Account View.

When a comment is selected, the background of the comment becomes yellow, the range of cells this refers to in your current Budget view will then also show with a matching background. This is useful if you have multiple comments, you can click on each comment in turn and easily identify the range of cells that relate to the comment, as the background will only show for one selected comment at a time.

The Budget comment may also relate to cells that are not in the current Budget View, in this case a warning message will be contained within the Comment:

If you hover over the sections of the Breadcrumb, you will get a screen tip to show more details, for example below the breadcrumb refers to Multiple Business Units, and the hover message displays the details as comma separated Business Unit names.