docs: def _insert_eups_version(c):
      """Insert information about the current EUPS tag into the configuration
      namespace.
  
      The variables are:
  
      ``release_eups_tag``
          The EUPS tag (obtained from the ``EUPS_TAG`` environment variable,
          falling back to ``d_latest`` if not available).
      ``version``, ``release``
          Same as ``release_eups_tag``.
      ``release_git_ref``
          The git ref (branch or tag) corresponding ot the EUPS tag.
      ``scipipe_conda_ref``
          Git ref for the https://github.com/lsst/scipipe_conda_env repo.
      ``newinstall_ref``
          Git ref for the https://github.com/lsst/lsst repo.
      ``pipelines_demo_ref``
          Git ref for the https://github.com/lsst/lsst_dm_stack_demo repo.
      """
      # Attempt to get the eups tag from the build environment
      eups_tag = os.getenv('EUPS_TAG')
      if eups_tag is None:
          eups_tag = 'd_latest'
  
      # Try to guess the git ref that corresponds to this tag
      if eups_tag in ('d_latest', 'w_latest', 'current'):
          git_ref = 'master'
      elif eups_tag.startswith('d_'):
          # Daily EUPS tags are not tagged on git
          git_ref = 'master'
      elif eups_tag.startswith('v'):
          # Major version or release candidate tag
          git_ref = eups_tag.lstrip('v').replace('_', '.')
      elif eups_tag.startswith('w_'):
          # Regular weekly tag
          git_ref = eups_tag.replace('_', '.')
      else:
          # Ideally shouldn't get to this point
          git_ref = 'master'
  
      # Now set variables for the Jinja context
      c['release_eups_tag'] = eups_tag
      c['release_git_ref'] = git_ref
      c['version'] = eups_tag
      c['release'] = eups_tag
      c['scipipe_conda_ref'] = git_ref
      c['pipelines_demo_ref'] = git_ref
      c['newinstall_ref'] = git_ref
  
      return c