I think I found some English language hard-coded strings in the upcoming Moodle 3.0 branch.
Added a 100% translated language pack (es_mx)
Added a new course
Added a tags block
Edited tag block settings
Choose 'Number of tags to display' dropdown menu
The three choices shown (default, official, both) are hard-coded English strings and not available for translation in AMOS.
Can you please check and, if true, add a new issue in the tracker. I know it is minor, but it is always good to improve Moodle a little bit more
Thanks in advance for your help.