I suspect bug 1682434 reduced a lot the problem here, from the profile I see us spending time in the same area. Could you please test with Firefox 86? The only other thing we could do here, that I plan doing actually, is to avoid highlighting fallback url heuristic results, they are the full url anyway, making it full bold doesn't bring any benefit and rather makes them less readable. It is an expensive highlight that has no real purpose.
Bug 1684667 Comment 7 Edit History
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I suspect bug 1682434 reduced a lot the problem here, from the profile I see us spending time in the same area. Could you please test with Firefox 85+? The only other thing we could do here, that I plan doing actually, is to avoid highlighting fallback url heuristic results, they are the full url anyway, making it full bold doesn't bring any benefit and rather makes them less readable. It is an expensive highlight that has no real purpose.