Finding a Standard Button (RequestUseSfdc) that is being excluded from page layouts?

In the metadata file for layouts, you’ll see that standard buttons are only specified for those that shouldn’t display: through a <excludeButtons> field. The description states:

List of standard buttons to exclude from this layout. For example, Delete excludes the Delete button from this layout.

I figured it would be easy to find these references since you could look through a given object’s buttons/actions and see what’s "standard" and understand what it’s doing/related to. However, there’s one showing up in my diffs that I can’t seem to find any reference to.

RequestUseSfdc is being excluded on Contact layouts in production, but not in sandboxes. It seems even if I deploy it without the exclusions into productions, they still stay there.

I found one question from 2010 that references it, but provided no answer to specify what it is.

I’ve done a couple things:

1. Hovered over all the actions/buttons in the layout editor to see if it showed. I found all other excluded buttons except that one.
2. Did a search through our metadata repository and could only find references to this on the contact layout.

The only hunch I have is that it’s related to DataDotCom. We don’t use it, but it’s possible we used it once or it’s "on" because of prior usage.

<excludeButtons>DataDotComClean</excludeButtons>
<excludeButtons>RequestUseSfdc</excludeButtons>