Is there a thing like good extensions and bad extensions on firefox. I mean, I don’t want to know about privacy and security of extensions right now, but does some extensions slow down the performance of firefox more than other extensions?
Also, how to distinguish these extensions from others? Does size of the extension matter? i.e., if the size of the extension is higher does that mean it’s eating more resources or will eat more resources.
Does a good extension run on all pages or only on the pages it’s needed? Is there a better way to handle extensions? Maybe disable some extensions which are not in use, idk!
The answer to your actual question is really complicated though, and very difficult to know for any given extension.
Take ublock for example, it needs to examine every element on every page, which is generally “bad”, but it’s going to remove resource hungry ads, which is “good”. The good part won’t show up in about:processes.
That said, browsers (supported by modern cpus) are so insanely good at examining elements that you just won’t notice the performance hit of a few dozen ms.
Problems only really arise when you encounter bugs.