Boomerang is an open-source library [1] for collecting performance telemetry. You're correct that it currently captures the battery level and other device characteristics. While Boomerang was not designed for the purpose of fingerprinting users, it captures many performance metrics and page characteristics on the beacon. Boomerang also only captures battery level, not charging time/discharging time (which we understand to be needed for the fingerprinting case). mPulse RUM itself (which is one of the services that utilizes Boomerang) does not do user fingerprinting -- we capture all of this data to look at aggregate performance.
Boomerang has been collecting the battery level in supported browsers for a while, but we don't consider it an essential device characteristic. In aggregate, it becomes interesting -- we can tell, for example, if certain paths through a customer's website correlate with high battery discharge, indicating possible post-page-load performance issues (like too many ads). Obviously there are better/others ways of doing this (such as the work being done on the Long Tasks API), measuring FPS, etc. But whenever things like the Battery API are available we love to capture all the data we can to see what interesting conclusions we can find out of it in our aggregate RUM data :) That being said, if the Battery API went away we would probably shrug, and look forward to more actionable performance metrics such as the Long Tasks API. PS, we know of customers and open-source users putting Boomerang on a couple thousand websites -- but that probably wouldn't account for 6% of page loads usage! [1]https://github.com/SOASTA/boomerang _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
