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, find the latest release on the sidebar. Builds can also be found at extensions.libreoffice.org.
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 is a zipped file with source code included. The file is built by zipping up relevant files, either with this PowerShell script or by hand. More options to build the extension are described in README_build.txt.
Most of the code is in the pythonpath folder as described here.