Revisions allow you to track differences between multiple versions of your content, and revert back to older versions.
Changed bitbucket link to a better example using yesterday's commit to the hfcc_global module.
Added link to Bitbucket commit that uses preprocess hook and a template file to theme the field.
Improved theme_mysite_pseudo_field() to add support for #field_name and streamline handling of #label_display. This could (and should) be expanded to allow passing of #attributes, too.