Here's a fun email from my engineering group. I've anonymized the product names and done light editing to protect the guilty...
On the Configuration page, there's a field called Time Interval, with the options Daily, Weekly, and Monthly. After much research, I have been unable to discover any functionality affected by this field. As such, it should be removed.
Here's the story in greater detail:
The field exists in [our older product], so we just copied it to [our brand spanking new] product. The going theory was that this field affects the default view for reports. I checked with the engineering lead, and the results of this field are captured in the time_slot_n column of the config database table.
We then confirmed that reporting doesn't read from this table. I also checked with members of the reporting and aggregations teams to see whether they used the data for anything. Aggregation found it commented out of the code, and reporting never heard of it. We then checked with the database team, and the best we could work out was that this once had something to do with [incredibly old ad network from first dot-com boom] (as I understand it, a product from the olden days, when banner ads were delivered by horse-drawn buggies).
No one is quite willing to say that the Time Interval option absolutely, positively does nothing. But no one seems to be able to work out any actual functionality. As such, I think we can safely remove it.
I think followed up with the sender, who works in the documentation, to find out what the documentation (written by the prior documenter) actually says about this feature. The contextual help continues on this pattern of clarity with something like:
Time Interval: Choose your time interval from the dropdown menu.