This is the new major ISOFIT 3x release that adds multiple new features, updates, and bug fixes.
**Main features**
- new handling of look-up-tables (LUTs), including the option to provide custom prebuilt LUTs
- centralized radiative transfer physics for more flexible development and experimentation
- test coverage for major functionality
- click command line utilities, including download of external data and example files
- a more flexible isofit.ini file used to discover various paths such as tests, data, and examples
- instructions for dev environment setup and a collection of setup scripts
- numpy implementation of the sRTMnet emulator (removes `tensorflow` dependency)
**Technical updates and bug fixes**
- cleaned up ray initialization to not rely on external calls
- updated authorship files
- wavelength checks to ensure that spectral grids obtained from the surface model or an externally provided wavelength file match the instrument specifics given in the input radiance cube
- support for the GAO instrument
- removal of package dependencies, including `matplotlib` and `gdal`
- removal of outdated docker image
- new test labeling for CLI workflows
- deprecation of `LibRadTran` support