I never found a way to identify them with that...best is to find a word or phrase that is as unique as possible and use that to search the fields. If you find several possibilities, I usually add a letter or number to each and then review the site to identify what is the proper label to update.

Keep in mind that some labels are used on more than one field at a time so make sure to test thoroughly. Also you may want to keep a log of the changes including the original text and the new text in case you need to change again or revert.

Last, keep in mind that localization changes are global and apply to your entire site. You cannot make changes just for single sub domain with this tool.