No, there is no “good” source for this data. You can probably find some not-so-good sources for browser statistics, including plugins, but such statistics suffer from several problems.
One of the main problems is the choice of bias. Anyone who collects and distributes statistics can only collect data from browsers visiting their site. An example is browser share; more technical sites report a higher market share in Firefox compared to more general sites. This is due to the fact that more technical people use Firefox more than others, and they most often visit a technical site.
An example for Unity is that Linux users are much less likely to visit a site that uses the Unity plugin because there is not one for Linux, so you don’t count the true percentage of people who have the Unity plugin installed.
Kdoto links are suitable for getting a basic idea of usage, but any statistics are likely to overestimate the percentage of users with X and - if you decide “I can live with the exception of 5% of users who don't have X”, you really exclude a higher percentage than this is.
Stephen p
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