“Firefox got faster for real users…” why include “real”? Are there fake users? Just strange phrasing.
I think they're distinguishing from synthetic benchmarks
Perhaps as opposed to "Firefox got faster in the benchmarks", which do not always correlate to how normal users use the web.
I assume it implies "we base our claims on data from real users, not artificial metrics"
Firefox's analytics allows Mozilla to analyze changes in the real world for Firefox users. Testing things like startup time and load times for actual users as opposed to synthetic benchmarks.