Starting with the next release of the FIT SDK, the zip file containing the FIT SDK source code, tools, and example files will no longer be available as a download from the developer site.
https://developer.garmin.com/fit/download/
Moving forward the source code for each FIT SDK will a be available in GitHub repos. When possible the SDKs will be available in the appropriate package manager. ie Maven, npm, Nuget, PyPI, etc. The FitCSVTool.jar, Profile.xlsx, ActivityRepairTool.jar, and the example files will be available in a new FIT SDK Tools repo.
The existing repos can be found here. The C & C++ SDKs and tools repos will be made available with the next release.
https://github.com/garmin/?q=fit-&type=all&language=&sort=
The zip file has been around since 2009 and had a pretty good run. But now that many of the SDKs have been available in package managers for a while, over three years for a few of them, it is time to deprecate the zip file.
The ETA for this is February or March of this year.