Knack drives our data dictionary and many database field names are not searchable for some reason. If the field value is "is_online_gift" a search for that won't return it, and if you search for just "online" it will sometimes come up. Needless to say it is flaky and given the fact that filenames, web urls, and things like database fields often use underscores or dashes it might be nice for the search index to treat them as spaces for the purpose of matching.
The front-end of our data dictionary is public:
Thanks for considering!