Configure with
cmake .. -DCONFIGURE_DOXY=ON
or
cmake .. -DDEV=ON
Then build the BornAgain API docs with
make doxycore
make doxygui
The results can be found in the html subdirectory of the build directory.
To inspect these docs, point your browser to
file://<absolute build directory path>/html/core/index.html
file://<absolute build directory path>/html/gui/index.html