My hidden field inf_custom_Browse History before Contact always is empty - how do i fix it?


I am using some forms added to my site via the code. They were built before me, and they have hidden fields, such as

<input name="inf_custom_Source" type="hidden" value="null" />
    <input name="inf_custom_BrowseHistorybeforeContact" type="hidden" value="null" />

Those are always empty when we receive the form submission. A colleague says they worked at one time. How do i get them to work now? I cannot find much in the docs, but if there is such a doc about this, I’d love to have the link.

I’m assuming BrowseHistorybeforeContact would show what user browsed before the form, this would really be helpful info!