segmentio/metalsmith-permalinks — pull request #24 by sanx (2014-11-06 01:58:50+00:00)
Title: added support for option 'collection', which makes this plugin only effect files belonging to a collection, such as the ones created by 'metalsmith-collections'

I think this is good alternative to setting "permalink: false" in the front matter for people who want to rely more on `metalsmith-collections`.