The following message displayed in the rename UI is not translatable:
This page opened in a new tab.
After you save this form, return to your original tab to make sure you save any changes you made there.
Just click on the 'Replace' link of any image field form to open the Rename UI in a separate tab. You will see the message in question there.
In 'src/Form/FileRenameForm.php', change...
$form['info'] = [
'#markup' => '<p>This page opened in a new tab.<br>After you save this form, <b>return to your original tab</b> to make sure you save any changes you made there.</p>',
];...to:
$form['info'] = [
'#markup' => t('<p>This page opened in a new tab.<br>After you save this form, <b>return to your original tab</b> to make sure you save any changes you made there.</p>'),
];Active
1.0
User interface
Issue #3490965: Fix non translatable message in rename UI
Automatically closed - issue fixed for 2 weeks with no activity.