fix(l10n): normalize de_DE to de before user manual build

[miaulalala]

☑️ Resolves

Relates to #13370

💡 Context

Every other Nextcloud project (server, apps, clients) syncs formal German as de_DE in Transifex. These docs are the outlier, using bare de — which confuses translators (not everyone is on both German teams) and keeps the translation memory from pooling with the mature de_DE TM used everywhere else.

The published URL (user_manual/de/) can't change — it's linked from many external sites (see discussion on the issue).

This PR decouples the two: it adds a build-time step (build/normalize_locale_codes.sh, wired into user_manual/Makefile's html target) that folds locale/de_DE into locale/de right before Sphinx builds, if de_DE exists. It follows the same pattern already used by change_file_extension.sh for .pot → .po renaming.

This is currently a no-op — locale/de_DE doesn't exist yet. It only takes effect once the Transifex resource for the user manual is reconfigured to sync German under de_DE instead of de, which needs to happen on the Transifex side (cc @rakekniven).

Opening as a draft to get eyes on the approach before the Transifex-side config change happens — cc @AndyScherzinger @nickvergessen since you both weighed in on the issue.

🖼️ Screenshots

N/A — build tooling change only, no rendered content changes.

✅ Checklist

• I have built the documentation locally and reviewed the output
• Screenshots are included for visual changes
• I have not moved or renamed pages (or added a redirect if I did)
• I have run codespell or similar and addressed any spelling issues

[nickvergessen]

I'm overly busy and not familiar with the new deployment mechanism, so I will stay out of this

[rakekniven]

Oh, that sounds good.
I’d be happy to write an announcement at Transifex before the change goes live.

Renaming a language at Transifex is not possible.
I can add "de_DE" language, which will be empty.
The sync needs to be adapted as well and after a sync the strings should be present in "de_DE".
Afterwards I will remove "de" language from project "Nextcloud user documentation" at Tx.

Question:
Where are the available languages for the documentation defined? In Sphinx, it should only be “de”, and on Transifex, “de_DE”.

[miaulalala]

Good question! There's no static list to edit — the available languages are derived dynamically from directory names in both places:

• Sphinx build (user_manual/Makefile): LANGS = $(shell touch locale/en && ls locale | grep -v source && rm locale/en) — just lists whatever folders exist under user_manual/locale/
• Language switcher template (user_manual/conf.py, available_languages): same idea, os.listdir(locale_path) over user_manual/locale/

So as long as build/normalize_locale_codes.sh runs before Sphinx builds (it does, wired into user_manual/Makefile's html target), it folds locale/de_DE into locale/de before Sphinx ever sees the directory listing. Sphinx and the language switcher will only ever see de.

On the Transifex side: once you add de_DE and the sync lands those files in the repo under user_manual/locale/de_DE/, our build script takes it from there — no further config needed on this end.

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Last updated: Wed, 15 Jul 2026 18:37:59 GMT

[AndyScherzinger]

Code looks good to me, but I have no knowledge myself on how generation and deployment works on the docs repo. So I'd be relying on @skjnldsv and @nickvergessen for that.

But generally would be happy if we can make the translation community happy with this.