From Green Dragon Creations:
Limits the size of the playlist file so that it doesn't exceed the limits of the current firmware. If there are more than 250 songs, MacEmThreeYou will create multiple playlist files. The song count is not checked until the end of a folder so if you have all the songs for one album in each folder, the whole album will be in the same playlist. Fixes a bug which caused only one folder within each folder to be processed. MacEmThreeYou now correctly processes all folders and all sub-folders within them. No longer renames the MP3 files as it builds the playlist because the 4.13e version of the firmware no longer has the file name comparison bug in it so all songs in a directory can be found by using their real names.
Ignores any file which it doesn't think is an MP3 file. This means it won't add icon files or other kinds of files which are stored along with the MP3 files on the Jukebox (including the archos.mod file).