Issue Check

• I have checked existing Issues and I feel this bug has not been raised

Hugo Version Check

• My Hugo version is within the supported range

Describe the Bug

Blowfish correctly generates hreflang alternate tags for translated pages via the IsTranslated check in head.html:

{{ if .IsTranslated }}
  {{ range .AllTranslations }}
    {{ $hreflang := .Language.LanguageCode | default .Language.Lang }}
    {{ if $hreflang }}
      
    {{ end }}
  {{ end }}
{{ end }}

This works correctly when a page has translations. However, it has two gaps:

1. Pages that exist only in the default language get no hreflang at all.

On a multilingual site (e.g. EN + IT + FR), Google expects every page to declare its language affinity via hreflang. Pages without any hreflang tag on a multilingual site can be deprioritized for indexing. This is likely a contributing factor to the common "Crawled - currently not indexed" status reported by Search Console users on multilingual Blowfish sites.

2. hreflang="x-default" is never emitted.

Google's hreflang specification recommends a x-default tag to indicate the fallback URL when no language match is found. Without it, Google has to guess which version is canonical for international users.

To Reproduce

Check the HTML code in a situation where:

• The website is multilingual
• Some posts have not translation

Expected Behaviour

layouts/partials/head.html should generate both

    <link rel="alternate" hreflang="x-default" href="...">
    <link rel="alternate" hreflang="xx" href="...">

Screenshots

No response

Platform

No platform-dependent

Hugo Version

hugo v0.160.1+extended+withdeploy darwin/arm64 BuildDate=2026-04-08T14:02:42Z VendorInfo=Homebrew

Blowfish Version

v2.88.1

Additional Context

Workaround via extend-head-uncached.html

Since extend-head.html is called with partialCached .Site (no page context), it cannot be used for per-page tags. However, Blowfish already provides extend-head-uncached.html which is called with full page
context. Users can work around the gap today by creating:

layouts/partials/extend-head-uncached.html:

{{ if .IsPage }}
  {{ $defaultLang := (index .Site.Languages 0).Lang }}
  {{ $defaultPermalink := "" }}

  {{ range .AllTranslations }}
    {{ if or (eq .Language.Lang $defaultLang) (not .Language.Lang) }}
      {{ $defaultPermalink = .Permalink }}
    {{ end }}
  {{ end }}

  {{ with $defaultPermalink }}
    <link rel="alternate" hreflang="x-default" href="{{ . }}">
  {{ end }}
  
  {{ if not .Translations }}
    <link rel="alternate" hreflang="{{ .Language.Lang }}" href="{{ .Permalink }}">
  {{ end }}
  
{{ end }}

This works but requires every multilingual Blowfish user to discover and implement it manually. The fix belongs in the theme itself.

Additional context

• Google's hreflang documentation:
  https://developers.google.com/search/docs/specialty/international/localization
• The x-default tag spec:
  https://developers.google.com/search/blog/2013/04/x-default-hreflang-for-international-pages
• Both proposed changes are fully backward compatible — sites without a multilingual setup are unaffected since AllTranslations on a monolingual site returns only the page itself, and .IsPage scopes the change away from home/section/taxonomy pages where Blowfish may handle things differently.

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