Hi,
First, please note that you have HikaShop 4.0.2, not 4.0.3.
The 4.0.3 version actually has a new interface for language file overrides so you might want to give it a go.
The search of the browser is probably not able to search in the popup. But the text you're looking for is in the translation file.
Copy it in a text editor on your local computer and search for it there and you should find it.
Note that there are two other ways to change that text:
- Instead of going through the HikaShop language override area, you can use the Joomla language override:
docs.joomla.org/Help39:Extensions_Langua...nager_Overrides_Edit
It is compatible with HikaShop.
- Since apparently your website is only in one language, you could directly edit the custom field via the menu Display>Custom fields and change the text of the title of the custom field.