The math is correct, see /about for methodology and this summary from the "How Scores Work" panel.

   About PWA Scores:

   • The main score shown is weighted for feature importance
   • Only stable (non-experimental) features are counted
   • Tap or hover any score to see:
      – Raw scores (simple % of supported features)
      – Experimental feature scores

▲ nchmy 3 hours ago | parent [-]

background capabilities is 0 for all browsers. there were other weird inconsistencies as well. We can completely leave to the side that your weighting scheme is surely arbitrary or perhaps even biased.

	▲	CharlesW 3 hours ago \| parent [-]
		Because they're experimental. Since that's confusing even with a key, it may be better to hide experimental features/categories by default. > We can completely leave to the side that your weighting scheme is surely arbitrary or perhaps even biased. Hover on any number to see both "raw" and "with experimental/non-standard features" scores. If you do this to the overall score, you'll see that Firefox benefits the most from this.