`KeyError: 'backrefs'` with `docutils==0.22`

[mgorny]

Describe the bug

context
When docutils is updated to 0.22, sphinx-tabs fails over removed backrefs key.

expectation
sphinx-tabs working.

bug

translator = <sphinx.writers.html5.HTML5Translator object at 0x7f934a6d8050>, node = <div: <button...><button...><button...>>

    def visit(translator, node):
        # Borrowed from `sphinx-inline-tabs`
        attrs = node.attributes.copy()
        attrs.pop("classes")
        attrs.pop("ids")
        attrs.pop("names")
        attrs.pop("dupnames")
>       attrs.pop("backrefs")
E       KeyError: 'backrefs'

sphinx_tabs/tabs.py:69: KeyError

problem
Since Sphinx 8.2.3 is already compatible with docutils 0.22 itself, the pin is going to be updated in the next release. This will cause projects using sphinx-tabs to fail.

Reproduce the bug

uv pip install -e .[testing]
uv pip install -U docutils
pytest

(optionally gh pr checkout 200 to get fixes for Sphinx 8.1)

List your environment

Package                       Version  Editable project location
----------------------------- -------- -------------------------
alabaster                     1.0.0
appdirs                       1.4.4
babel                         2.17.0
beautifulsoup4                4.13.5
bs4                           0.0.2
certifi                       2025.8.3
charset-normalizer            3.4.3
coverage                      7.10.6
docutils                      0.22
idna                          3.10
imagesize                     1.4.1
iniconfig                     2.1.0
jinja2                        3.1.6
markdown-it-py                3.0.0
markupsafe                    3.0.2
mdit-py-plugins               0.5.0
mdurl                         0.1.2
myst-parser                   4.0.1
packaging                     25.0
pluggy                        1.6.0
pygments                      2.19.2
pytest                        7.4.4
pytest-cov                    6.3.0
pytest-datadir                1.8.0
pytest-regressions            2.8.3
pyyaml                        6.0.2
requests                      2.32.5
rinoh-typeface-dejavuserif    0.1.3
rinoh-typeface-texgyrecursor  0.1.1
rinoh-typeface-texgyreheros   0.1.1
rinoh-typeface-texgyrepagella 0.1.1
rinohtype                     0.5.5
roman-numerals-py             3.1.0
snowballstemmer               3.0.1
soupsieve                     2.8
sphinx                        8.2.3
sphinx-tabs                   3.4.7    /tmp/sphinx-tabs
sphinxcontrib-applehelp       2.0.0
sphinxcontrib-devhelp         2.0.0
sphinxcontrib-htmlhelp        2.1.0
sphinxcontrib-jsmath          1.0.1
sphinxcontrib-qthelp          2.0.0
sphinxcontrib-serializinghtml 2.0.0
typing-extensions             4.15.0
urllib3                       2.5.0

[mitya57]

The fix is trivial, I made PR #207 for it.

[mgorny]

Thank you!