The example produces a source-by-route coverage matrix for three original documents. English and French index sources exist; only the English verify source exists. With fallback enabled, /fr/verify/ uses English. With fallback disabled, that route is absent while the French index remains. The reading tool calculates policy expectations; it does not invoke MkDocs, translate content, or report a successful site build.
List the actual source languages
The fixture is docs/index.en.md with title Practice notes, docs/index.fr.md with title Notes de pratique, and docs/verify/index.en.md containing Verify the source record. There is no verify/index.fr.md. The short French title is authored content, not plugin-generated translation. Keep requested locale, selected source, body language and fallback flag in separate columns. A localized navigation label does not establish that the page body has a localized source, and a route prefix is not evidence of translated paragraphs.
Use the suffix structure with English default/build enabled and French build enabled. State use_directory_urls true for the intended slash-terminated routes. Before a native build, confirm the installed plugin, MkDocs and theme versions support the configuration. Keep a configuration revision with the source inventory. After the build, inspect the generated files to see whether your installed release and theme produce the expected routes.
Compare both fallback policies
With fallback_to_default true, expect / and /verify/ from English, /fr/ from French, and /fr/verify/ from English fallback. Four routes exist, but only one of the two French routes has a French source. With fallback false, the two English pages and French index remain; /fr/verify/ is omitted. Do not describe the whole French site as missing because one translation is absent. The page lets you inspect the affected verify record and then restore the full matrix.
Use fresh separate output directories for the native comparisons rather than letting an old generated page linger. Record exact source/configuration revisions, installed versions, build exit result, output manifest and content markers. The expected matrix needs actual existence/source/content observations after each build. Changing the fallback control in this aid changes the prediction, not an output directory. A previous screenshot from the enabled policy cannot confirm that the disabled build removed the verification route.
Check theme and links separately
MkDocs theme localization concerns theme elements, not translation of the documentation body. Language metadata, fallback banners, switcher deep links and navigation also require their own output checks. If adding a link to verification, use the neutral source reference verify/index.md for the intended fixture and inspect the generated destinations under both policies. Do not assume the route matrix demonstrates link rewriting or that a translated title proves every control has been localized.
Finish by reporting availability and translation coverage separately. A useful summary can say the French verification route is available by English fallback rather than counting it as French translation. Keep native Markdown and actual builds authoritative, preserve earlier policy results under revision labels, and recheck when sources, languages, URL settings or fallback behavior change. The matrix makes the missing translation actionable without turning it into an invented build failure or an automatic translation promise.
Make your own working example
Build an original MkDocs i18n coverage-policy reading tool. Source inventory: index.en.md title Practice notes; index.fr.md title Notes de pratique; verify/index.en.md text Verify the source record. No verify/index.fr.md. Intended suffix structure, English default/build true, French build true, directory URLs true. Native installed versions/builds are not measured.
Provide Fallback on, Fallback off, French verify only, All routes and Reset buttons. Enabled policy predicts / from English index, /verify/ from English verify, /fr/ from French index, /fr/verify/ from English fallback. Disabled retains first three and marks French verify absent. Show requested locale, source, content language, fallback status and expected existence, keeping missing translation distinct from missing entire locale.
Compute available-route and French-source counts from the record matrix. Filtering must not redefine overall coverage denominators. Show the verify route's English marker when fallback applies; never call it French translation. State actual native output remains unobserved. Keep theme UI language, HTML lang, banners, switcher and link rewriting outside this prediction. Preserve the unchanged source inventory while comparing explicit policy switches.
Use one self-contained HTML file with no remote dependency. Keep the initial sample, output, and labeled controls near the top. Use at least 16px text, strong contrast, visible focus, and a stacked layout at 360px without horizontal overflow. Use explicit type=button click handlers and explicit DOM selectors; do not depend on native form submission. Clear stale feedback when task inputs change. Render entered text safely. Keep practice data local to the current page; do not imply saving, sending, or production integration. Return only the finished HTML.
Annotate the missing translation
Retain Markdown sources and actual output manifests in the MkDocs project. In an HTML review matrix, NOS lets you revise eligible static coverage notes visually without AI regeneration. Clarify that the verification route is English fallback before the translation handoff.