What is the JQL operator "featuresOf" ?

[David Spalding]

A contractor has used a query operator that I can't find in the docs, featuresOf. I'd like to use this more but need to understand it. 

E.g. query

project = ABC AND issuetype != Objective OR key in featuresOf("project=ABC") ORDER BY Rank ASC

[Jack Brickey]

Not something that I am familiar with an out-of-the-box JQL. I suspect it’s associated with an add-on.

[Del Jensen]

@Jack Brickey  , I agree.  Looks to be part of this add-on

https://confluence.cprime.io/display/JJUPIN/Pre-defined+JQL+functions