The id of the comment that is being commented on.
Targets in the parent.* namespace are populated for Facebook Pages comments on comments. Note that Facebook currently permits comments to go only one level deep. Users can comment on original content and those comments can have 'child' comments but the thread connot go deeper than that.
- Filter for comments on a specified comment:
facebook_page.parent.id == "12345678"
Target service: Facebook_Page
Always exists: No