Pull Request for Issue #45567 .

Summary of Changes

This PR resolves an issue where values appended to a <limitbox> XML form field using the append attribute were incorrectly displayed with a J prefix (e.g., J35, J40, etc.) due to Joomla attempting to translate J{value} language keys that might not exist.

To fix this, the PR now checks if a language string exists for J{value} before applying the translation. If the key exists, it uses the translated text; otherwise, it uses the raw number as-is. This maintains compatibility with existing language strings while improving flexibility for custom use cases.

Testing Instructions

1. Create a <field type="limitbox" append="35,36,37 /> in an XML form (or edit an existing form field if you don't want to create one, such as the limitbox field at administrator/components/com_users/forms/filter_groups.xml by adding the append attribute to it)
2. Load the form and observe the dropdown options.
3. Even though there is not going to be a language var for J35, J36, J37, instead of the dropdown showing a J prefixed entry for the text on the option, it just shows the raw text ( 35, 36, 37)

Actual result BEFORE applying this Pull Request

• Options appended from append= show up with a J prefix, e.g., J35, J36, J37, even though these language keys likely don't exist.
• Values are technically correct, but labels are confusing or incorrect.

Expected result AFTER applying this Pull Request

• If a J{value} language key exists (like J25), it's translated.
• If it doesn't exist, the raw value (e.g., 35) is used directly for the option label.

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed