Some dynamic values and search facets are not localized in the Modern Frontend

What steps does it take to reproduce the issue?

1. Change the Modern Frontend interface language to Spanish.
2. View a dataset containing an ingested tabular file.
3. Open the file details/metadata.
4. View search results with facets such as Subject, Author Name, and Author Affiliation.

- When does this issue occur?

When using the Modern Frontend in a non-English language. We observed the issue while testing the Spanish interface.

- Which page(s) does it occur on?

Dataset/file display pages
File metadata/details
Search results/facet sidebar

- What happens?

Some static UI text is translated correctly, but dynamically generated values and some Dataverse-controlled labels remain in English or use English-style formatting.

Examples observed:

1. File information

• File size is displayed as 180.3 KB instead of the Spanish locale format 180,3 KB.
• File type remains Tab-Delimited.
• The system-defined file tag Data remains in English.

2. Search result dates

Dates displayed in search results also remain in English when the interface is set to Spanish. For example, an English-formatted date such as Sep 2, 2026 should instead be formatted according to the active Spanish locale.

3. Search facets

• The Más... link is translated, but several facet headings remain in English, including:
• Subject
• Author Name
• Author Affiliation

4. Controlled Subject values also remain in English, for example:

• Social Sciences
• Arts and Humanities
• Medicine, Health and Life Sciences
• Earth and Environmental Sciences
• Law
  User-supplied metadata such as author names and institutional affiliations should remain unchanged. The issue is with interface labels and Dataverse-controlled display values.

5. Facet result counts also do not appear to use locale-aware number formatting.

   For example, values are currently displayed as:
   53305
   4940

   In English, these would normally be formatted as:
   53,305
   4,940

   In Spanish, the formatting should follow the active Spanish locale, for example 53.305 or 53 305 and 4940 for es-ES, rather than using a fixed English or unformatted representation.

- To whom does it occur (all users, curators, superusers)?

all users viewing the Modern Frontend

- What did you expect to happen?

When a supported interface language is selected, locale-sensitive values and Dataverse-controlled interface/display labels should consistently follow the active locale where translations are available.

For example:

English: 180.3 KB
Spanish: 180,3 KB

Search facet headings should also be localized, and controlled vocabulary labels such as Subject values should use their translated display labels where available.

Dataset version identifiers such as 4.0 or 3.1 should not be locale-formatted, since the period is part of the version identifier rather than a decimal separator.

Which version of Dataverse Frontend are you using?

v. 6.10.1 build iqss-4 | frontend version: 371cf9773

Any related open or closed issues to this bug report?

We have not identified an existing issue that covers these specific localization problems.

Start with the dataset/file display, file metadata, and search-results facet entry points described in the report, then trace locale handling for file sizes, dates, facet labels, controlled subject values, and counts. Compare the Spanish output with the expected examples and existing localization behavior. Done means supported interface languages consistently format locale-sensitive values and translate available labels without changing user-supplied metadata or version identifiers.