explanation for phabricator labels "Bug Report" and "Feature Request"?

[Daniel Kahn Gillmor]

hey folks--

i've submitted a few tasks to phabricator recently (e.g. T3345, T3323),
where i mis-applied the labels "bug report" and "feature request".  i
thought i was submitting sensible labels, but clearly i don't understand
the semantics of the labels as they're intended to be used on
phabricator.

Is there documentation for how we should use those labels so i can get
it right in the future?

   --dkg