Because uBlock Origin ships with the default filter lists, so that it can work immediately out of the box without having to remotely fetch these filter lists at launch time (updated versions of these lists will be automatically fetched some time after launch).

It's not uncommon that the remote servers hosting the lists fail to respond, which would cause the extension to "malfunction" if this happened after first install -- these lists are key for the proper functioning of the extension (at least in its default out-of-the-box settings). I want the extension to work properly immediately after 1st install.

The size of uBlock Origin as downloaded from AMO or Chrome store is ~1.5 MB (because it's compressed). The compressed package would be ~650 kB without the 3rd-party lists (the content of these lists are not javascript code).

Javascript size is a weird metric, and the plot is useless without context. The plot does not even state for which browser the metric was collected (or is it the repository size? That would be completely useless, as uBlock's and uBlock origin's repositories include versions for different browsers.) Because when I add the sum of all .js files in uBlock's repository, I get 1.08MB. Heck, the whole src and platform directories combined are 2.8MB, and that includes both the Chrome and the Firefox version! Can you point to a source for that plot?

> The plot does not even state for which browser the metric was collected

It's there in the title of the plot. Did you even looked at the plot?

> Can you point to a source for that plot?

I did the plot few days ago, I simply installed all those extensions and calculated JS size on disk.

Why my comment has -4 points? I simply stated the truth, everybody can measure size of JS of these extensions. I did not count default filter list to size of JS, I only counted actual JS code and uBlock origin has simple more JS code than both Adblock and Adblock plus.

If I lied I would understand the downvotes but I didn't lie. I was also surprised that uBlock origin is bigger than adblock, especially when it's name sounds like something much much simpler and smaller but the fact is that size wise they are practically the same.

Possibly because in reality the resources consumed while at rest (disk storage) are magnitude less important than the resources consumed while running (memory/CPU cycles).

Regardless, uBlock results in more performant web browsing.

I switched Firefox from Adblock Plus to uBlock Origin on several different machines, the oldest being a 2007 vintage Core 2 Duo laptop Win 7, which lets 3 gigabytes of the machine's 4 be used. I couldn't tell any subjective difference in any of the installations.

If I have to formally measure the response time difference in response in an interactive app, it's below the don't care threshold.