The theme is incompatible with Australis. I miss the orange buttons too, but unfortunately I currently have too little time for a complete rewrite.
If you think this add-on violates Mozilla's add-on policies or has security or privacy issues, please report these issues to Mozilla using this form.
Please don't use this form to report bugs or request add-on features; this report will be sent to Mozilla and not to the add-on developer.
Urlbar verified status background for Firefox 16 (and above)