This add-on inserts lexical and interlinear data from SIL FieldWorks into LibreOffice. Other features include Data Conversion using SIL Converters.
To download the add-on, go to https://extensions.libreoffice.org/extensions/lingtools. Source code is on github.
Help (including installation instructions) is available from the menu, or you can download it here: Linguistic Tools Help.pdf. For complete version history, see README.txt
The .oxt file is a zipped file with source code included. Most of the code is in the pythonpath folder as described here.
Information about how to build the add-on is in README_build.txt