These language data files only work with Tesseract 4.0.0. They are based on the sources in tesseract-ocr/langdata on GitHub. (still to be updated for 4.0.0 - 20180322)
These have models for legacy tesseract engine (--oem 0) as well as the new LSTM neural net based engine (--oem 1).
The LSTM models (--oem 1) in these files have been updated to the integerized versions of tessdata_best on GitHub. So, they should be faster but probably a little less accurate than tessdata_best.
tessdata_fast on GitHub provides an alternate set of integerized LSTM models which have been built with a smaller network. tessdata_fast files are the ones packaged for Debian and Ubuntu.
The legacy tesseract models (--oem 0) have been removed for Indic and Arabic script language files.
Get language data files for Tesseract 3.04 or 3.05 from the 3.04 tree.
More information and a complete list of all languages is available in the Tesseract wiki.