Folder "basic-py" has OSIS generated from basic USFM through the Python usfm2osis.py script.
Folder "basic-pl" has basic OSIS generated from basic USFM through the Perl usfm2osis.pl script.
Folder "full-py" has OSIS generated from full USFM through the Python usfm2osis.py script.
Folder "full-pl" has basic OSIS generated from full USFM through the Perl usfm2osis.pl script.
Both scripts are maintained by the CrossWire Bible Society.