The build was tested on Ubuntu 22.04 (and macOS Ventura 13.5 for development purposes)

1. install dependencies:

   sudo apt install make graphviz

2. run cmake with options:

   -DUSERVER_BUILD_ALL_COMPONENTS=1 \
   -DUSERVER_BUILD_TESTS=1 \
   -DUSERVER_BUILD_SAMPLES=1 \
   -DCMAKE_CXX_STANDARD=20 \
   -DUSERVER_DEBUG_INFO_COMPRESSION=z \
   -DCMAKE_BUILD_TYPE=Debug \
   -DCMAKE_C_COMPILER=... \
   -DCMAKE_CXX_COMPILER=...

   (you might want to add some options depending on your environment)

3. in userver folder run:

   make docs BUILD_DIR=/absolute/path/to/build_dir
   make docs-upload BUILD_DIR=/absolute/path/to/build_dir

   or

   make docs-internal BUILD_DIR=/absolute/path/to/build_dir
   make docs-internal-upload BUILD_DIR=/absolute/path/to/build_dir OAUTH_TOKEN=...

4. docs will appear in $BUILD_DIR/docs, warnings will be printed to $BUILD_DIR/doxygen.err.log

After building the documentation, you can add hard links to the files to be changed. For example, I'm going to change customdoxygen.css:

frontend@PC:~/Desktop/userver$ rm docs/html/customdoxygen.css
frontend@PC:~/Desktop/userver$ ln scripts/docs/customdoxygen.css docs/html/customdoxygen.css

Now it is possible to use tools like LiveServer