Fine, in between there were updates in the RDT, and the current yaml script (from https://gitlab.com/dirac/dirac/-/blob/master/.readthedocs.yaml) looks like:

version: 2

build:
  os: ubuntu-22.04
  tools:
    python: "3.12"
  apt_packages:
    - cmake
    - gfortran
    - gcc
    - g++
    - git
  jobs:    
    post_checkout: 
      - git submodule update --init --recursive
    install:
      - python3 -m venv venv
      - . venv/bin/activate
      - python3 -m pip install "sphinx<7.0.0" sphinx_rtd_theme sphinxcontrib-bibtex
      - pip list
      - lsb_release -a
    pre_build:
        - ./setup $READTHEDOCS_OUTPUT
    build:
      html:
        - cd $READTHEDOCS_OUTPUT; echo "I am in the directory:";pwd; make VERBOSE=1 html; cd html; echo "content of html:"; ls -lt; ls -lt _static