I've found an untranslated end-user-facing string, "-- Please Select --", used in variations. I translated it to Brazilian Portuguese in my local copy using the Codestyling Localization plugin, then went to
http://languages.getshopped.org/ to also provide it, but I couldn't find it there, even after searching for variations on these words. In fact, GlotPress says there are no untranslated strings, although the translation itself is considered only 90% complete, and Codestyling tells me there are 179 untranslated strings in WP e-Commerce 3.8.8. So, my guess is that the translation source used by WPEC's GlotPress is out-of-date.
Can someone please update it, or provide instructions on how I might provide this and perhaps other translations upstream?