What is the use of ApplicationResources.groovy file in Grails 2.5.1?

I am working on a old project made on Grails 2.5.1 and I came across the file 'ApplicationResources.groovy'.

Contents of the file were as below -

    module1 {
        dependsOn "chosen","datePicker"
    }

    module2 {
        dependsOn "maskedInput", "timePicker"
        resource url: "js/fullCalendarNew/lib/main.css"
        resource url: "js/fullcalendar/fullcalendar.print.css", attrs: [ media: 'print' ]
        resource url: "js/fullCalendarNew/lib/main.js", disposition:'head', nominify: true
        resource url: "js/custom_calendar.js"
        resource url: "css/calendar_popup_form.css"
        resource url: "js/jquery.bpopup-0.7.0.min.js"
        resource url: "js/fullcalendar/jquery.qtip-1.0.0-rc3.js"
    }

It seems like files consists of dependencies of various modules, but how does it work, what's the syntax to define such dependencies ? I couldn't find any documentation either on Grails official website.