As :jmaher and :ahal have both noted, we need a way to further generalize defining and setting up the events that will be used to retrieve perf measurements in Raptor. Right now the measurement content web extension script needs to know specifically which events to turn on handlers for and to grab/measure. That comes from the raptor test INI file. If possible, it would be better to make this more general and flexible so it will be easier to add future measurement types. Instead of using the same webext measurement content script each time, one idea is to only inject the handlers specific to what the test requires (similar to how talos pageloader does it now). However it may be tricky as at the same time, the background raptor webext runner script needs to know exactly what measurements are expected so it can time out if they aren't received, etc. Also some events are browser specific i.e. first-non-blank-paint vs first-contentful-paint. Investigate a better solution. :ahal noted perhaps an 'events' folder with event-specific and browser-specific content code kept there.