bigquery-etl VS Servo

I don't know how many folks will see this, and of those that do I don't expect many will necessarily be moved by what I say here. I'm going to say it anyways, however, and then I may never look at this thread again. I'm the person who designed the download token scheme that is discussed in this article, and, while I understand all of the concerns and suspicions, I believe that the way we designed this and the way we handle our telemetry data means that this is not the privacy violation some of you are claiming it is. Also, to be clear, I am speaking for myself here, these are my own thoughts and opinions, and I am not representing Mozilla in any official capacity.

So, a download token is a UUID associated with a unique download event. It gets generated when you click the 'download' link, added to the installer, and then passed through to the installed browser. It is returned to us in the telemetry pings that the browser sends back to our telemetry ingestion endpoints. When the download happens, on the server side we capture the download token and the GA session ID and store those in a table. There is nothing else stored in this table.

Having access to this table means that you can correlate the user's activity on the Mozilla website that GA provides with the telemetry data that Firefox sends us. The website activity contains URLs that the user visited, so we consider this "category 3" data (see https://wiki.mozilla.org/Data_Collection#Data_Collection_Cat...), quite sensitive. For that reason this table has highly restricted access, only a small number of individuals are able to get to it.

Access restrictions offer no protection against subpoenas, of course. But I believe you can safely maintain your anonymity by opting out of our telemetry gathering, because when you opt out of telemetry we delete all of the historical telemetry data we have collected for your Firefox profile. Everything, including all of the records that contain the download token.

If this happens, all we are left with is that original record with the download token and a GA session. The download token can no longer be correlated with your telemetry data, and we have no way of associating your Firefox installation with your GA session, not even under subpoena. And this is all assuming that you haven't blocked GA, or that you haven't specified 'Do Not Track' before visiting our website. If you've done either of those things, we won't have a GA session ID for you to begin with.

Oh, incidentally, we never store any IP addresses or other PII in our telemetry data. That all gets scrubbed during ingestion.

Again, I don't expect this to have much impact, but I'm sharing what I know to counter some of the more extreme claims that this removes the ability for Firefox users to remain anonymous.

Finally, we have the obvious question: Why we would even do this? Believe it or not, understanding your user base does actually have some value in serving that user base. For most of Firefox's existence, there has been no trustable feedback loop. Sure, folks out there in the world have opinions, and share them, but opinions differ, and anecdotes are not data. If one person thinks most users will like a particular change, and someone else thinks they won't, nobody can prove their point in any meaningful way. The folks making decisions about Firefox have been flying blind. And, as many of you in this thread have pointed out, it hasn't necessarily been going that well.

In Firefox's early years, there was lots of low hanging fruit, and the competition was a poorly maintained Internet Explorer, so it was easy to win a bunch of market share. Then Chrome came on the scene with their effectively limitless budget and famously data driven product process. We'll never match their budget, but we can try to make choices based on data instead of just letting whoever has the most organizational power decide. My team has spent the last few years building out a data infrastructure that we hope will support better decision making going forward while still trying to honor user privacy and choice. This is a tough balance to strike, and we're far from perfect, but we do our best.

You can learn about or data collection infrastructure and policies in great detail on our docs site (https://docs.telemetry.mozilla.org/index.html), and you can see nearly all of the code that handles our data ingestion and processing in our public repositories (https://github.com/mozilla/gcp-ingestion and https://github.com/mozilla/bigquery-etl).

I used to work on Mozilla's data platform. That stuff is all open source. See e.g. https://github.com/mozilla/gcp-ingestion/ for the ingestion pipeline, https://github.com/mozilla/bigquery-etl for queries/ETL, and https://github.com/mozilla/looker-spoke-default/ for looker model definitions for that data.

Also go read the docs at https://docs.telemetry.mozilla.org/. Those will give you insights into every way they use data.

I've never seen a company that's more open about their data usage.

Servo, the embeddable, independent, memory-safe, modular, parallel web rendering engine

> Is there any easy to use/hack HTML layouting engine where I could experiment with custom CSS attributes and bridge that gap? Would anything from Servo be suitable?

Servo could be used for this. You'd want to add support for parsing the CSS properties themselves to the style crate in https://github.com/servo/stylo and then the layout implementation to the layout2020 crate in https://github.com/servo/servo. You do effectively get a whole browser though.

I'm currently working on building a lighter weight / hackable layout engine based on a combination of https://github.com/servo/stylo (for css parsing and selector resolution), https://github.com/DioxusLabs/taffy (for box-level layout) and https://github.com/pop-os/cosmic-text (for flow/inline layout). I expect to have something decent in around 6 months

Neither of these setups currently have any support for pagination though.

Great to see some competition still alive in browser engine development. See also Servo (previously part of Mozilla) https://servo.org/ - that and Ladybird are still very underdeveloped compared to every day browsers.

It's a huge shame that there are no nightly builds of ladybird to try out but I assume that's because they just don't want the bug reports (if everything doesn't work it's pointless getting random bugs filed).

I haven't messed with it yet but from looking into it, this should absolutely work.

https://github.com/servo/servo/wiki/Building-on-ARM-desktop-...

don't know, there was a downtime in 2021 and 22 but since 2023, contributions look back to where it was before .. https://github.com/servo/servo/graphs/contributors

The world has moved on though to opinionated tools, and Rust isn't even the furthest in that direction (That would be Go). The equivalent of those two lines in Cargo.toml would be this example of a basic configuration from the jacoco-maven-plugin: https://www.jacoco.org/jacoco/trunk/doc/examples/build/pom.x... - That's 40 lines in the section to do the "defaults".

Yes, you could add a load of config for files to include/exclude from coverage and so on, but the idea that that's a norm is way more common in Java projects than other languages. Like here's some example Cargo.toml files from complicated Rust projects:

Servo: https://github.com/servo/servo/blob/main/Cargo.toml

rust-gdext: https://github.com/godot-rust/gdext/blob/master/godot-core/C...

ripgrep: https://github.com/BurntSushi/ripgrep/blob/master/Cargo.toml

socketio: https://github.com/1c3t3a/rust-socketio/blob/main/socketio/C...

1. Servo

It won't don't worry. There already are forks, for the worst case scenario. And Servo is on its way. Not yet ready, but it will be. Originally, from Mozilla kitchen.

To pain broad strokes, the layout phase (~= take the HTML, take the CSS, determine the position and size of boxes) is largely sequential in production browser engine today. Selector matching (~= what CSS applies to what element) is parallel in Firefox today, via the Stylo Rust crate originally developed in the research browser engine Servo. Servo can do parallel layout in some capacity (but doesn't implement everything), https://github.com/servo/servo/wiki/Servo-Layout-Engines-Rep... is an interesting and recent document on the matter.

Parallel layout is generally considered to be a complex engineering problem by domain experts.

https://hacks.mozilla.org/2017/08/inside-a-super-fast-css-en... is a really cool article that is related, that is a few years old but what it says is largely correct today.