get_string() now looks for message string files in location <lang>local amongst other locations. However help.php strangely chooses locations in $CFG->dirroot or $CFG->dataroot depending upon whether the language is en_utf8 or not and never checks <lang>_local at all. This is not consistent with regard to searching for message string files as if you have <lang>_local messages you would expect help files to be located in <lang>_local/help. Also if you have your own language setting of my<lang> say in $CFG->dirroot you would expect help files to be located in $CFG->dirroot/land/my_<lang>/help.
The attached patch addresses this inconsistency and extends search locations for help files. It still searches the same locations as before, and the order of searching for each language has been modified to: