I remember that there was a decision to place the language files of standard elements in the moodle/en_utf8 folder and the language files of translated files in moodledata/lang/mylanguage_utf8. The search block is part of the standard, but it contains an own language folder for en_utf and fr_utf8. These language foldr should be moved.
If we don't do this we will get problems with fast growing moodle packages and chaos in translations. To place the non en_utf8 language files in the moodledata folder had the reason in to big moodle packages