$ ag derivative
Fragments/articleTeaser.gql
Fragments/eventTeaser.gql
Fragments/article.gql
Fragments/event.gql
Fragments/userGroup.gql
Queries/libraryMyContent.gql 

$ ag derivative -l | oneline
Fragments/articleTeaser.gql Fragments/eventTeaser.gql Fragments/article.gql Fragments/event.gql Fragments/userGroup.gql Queries/libraryMyContent.gql

$ emacs $(ag derivative -l | oneline)