My Wireshark trial of Firefox 148 showed that its AI termination move disables generative features, but leaves telemetry and advertizing untouched. Six months later, Mozilla’s CEO has called the move possibly the astir important AI characteristic of all. I retested it successful Firefox 155.
In this article- Humility arsenic strategy
- The remark conception runs its ain test
- Retesting Firefox 155
- The move has grown
- Telemetry does not understand “blocked”
- Advertising continues, and Temu says hello
- Tante sounds the essay
- The astir important switch
Firefox promises to protect users from companies spying connected their clicks during onboarding. The AI controls are not mentioned anyplace successful that flow. Screenshot: Marius Quabeck.My first trial of Firefox’s AI termination switch apparently reached readers I had not expected. I was told that the article made its measurement into Mozilla’s soul Slack and was discussed there. The verdict: a “hit piece.” The truth that my erstwhile Firefox article had been featured connected the screen of the US version of Linux Magazine astir apt did not help. Anyone who publication it will cognize that its halfway consisted of preferences, big lists, and timestamps. The guidance is nevertheless unsurprising. It is simply a acquainted consequence erstwhile personification holds Mozilla’s ain behaviour up to the company. It is not my responsibility if Mozilla does not for illustration what my tests revealed astir its ain behavior.
My erstwhile Firefox article was featured connected the screen of the US version of Linux Magazine, Issue 309 (August 2026). Photo: Marius Quabeck.To beryllium clear, I cognize that the AI termination move does not declare to disable telemetry aliases advertising. I tested some again because they were portion of my erstwhile investigation, and because the consequence to that article showed why the favoritism matters. Many readers told maine they had nary thought really overmuch search Firefox performs successful the first place. Others had genuinely understood the AI termination move arsenic a cosmopolitan disconnected move for AI, telemetry, and advertising. Here is an idea, Mozilla: either grow the existing move aliases put a 2nd 1 adjacent to it.
Six months later, Mozilla’s activity sounds different. On August 25, CEO Anthony Enzor-DeMeo published an effort pinch the singular title “Trust is earned. Consent is asked. AI skipped both.” Reading it is disorienting successful places: a connection from the ivory building that reaches precisely the conclusion critics had reached months earlier.
Humility arsenic strategy
Enzor-DeMeo originates pinch his first time arsenic CEO successful December 2025. In interviews astir his appointment, he had talked astir AI successful the browser; aft all, the features were optional. Then came the backlash. “It was a gut punch. Frankly, I deserved it,” he writes. “I said the correct words and still missed the message.” One of his first decisions arsenic CEO was truthful not to motorboat different AI feature, but to build the move that turns them each off. He intelligibly dislikes the sanction “kill switch,” preferring AI Controls. He says he accelerated the task partially for individual reasons: he, too, was tired of AI popping up everywhere.
He had been proud, he writes, that Mozilla could fto users determine “how they AI.” Then the characteristic shipped, followed by the condemnation to which the effort gives a paragraph of its own: “Almost cipher utilized it.” In the months aft release, astir 1 percent of users reportedly switched disconnected each AI and 3 percent abnormal individual features.
The CEO’s mentation is that AI has nary fixed definition. Translation is instrumentality learning of the benignant that has existed for decades; generative AI is only 1 subset. Most users near translator enabled while tending to cull the generative features. That is not a free pass, he concedes, citing Pew Research: astir half of US adults now usage AI chatbots, yet 59 percent do not spot US companies to create AI responsibly. His conclusion is that, successful a world wherever companies unit AI connected their users, Firefox’s strongest statement is “choice and agency.” The last statement has the makings of a poster: “The astir important AI characteristic whitethorn beryllium the expertise to move it off.”
By the standards of Mozilla’s accustomed communications, this is remarkably self-critical. It is besides clever nationalist relations. The communicative retrospectively turns a concession to protesting users into impervious of Mozilla’s closeness to those users. And it rests connected a instauration straight applicable to this test: the numbers showing who flipped the switch. I will return to those numbers shortly.
Enzor-DeMeo promoted his effort successful a LinkedIn post that collected 537 reactions and 53 comments wrong a week. Nearly each instrumentality he uses had gained an AI characteristic this year, he wrote, and he could not retrieve being asked first. The replies are much revealing than the station itself.
Product head Olivia O’Hara tried it for herself and installed Firefox from scratch. Her finding: the onboarding travel does not mention that Firefox contains AI features astatine all, fto unsocial that location is simply a move for them. To find it, users person to unfastened the hamburger menu, participate Settings, and prime a dedicated tab. “It feels buried,” she wrote, suggesting that the one- and three-percent figures mightiness beryllium artificially debased because hardly anyone discovers the switch. Jed Wheeler added dryly that debased usage successful this lawsuit simply meant mediocre UX. The CEO replied that Mozilla was ever unfastened to UX feedback, but had tried to make the move easy to find: “Settings -> AI Controls.” That is precisely the way O’Hara had conscionable described arsenic buried.
Marketing advisor Shweta Bhatade captured the prevailing temper of this package year: each instrumentality she uses gained an AI panel, nary asked first, and aft a while it stops emotion for illustration a characteristic and starts emotion for illustration thing happening to you. Enzor-DeMeo responded, “Great insight!” The aforesaid observation, made by a journalist six months earlier, was reportedly treated wrong his institution arsenic a deed piece. Another commenter, Andres Servin, put the halfway favoritism neatly: “optional” and “controlled” are fundamentally different. Users for illustration the doorway locked by default to 1 that tin beryllium locked connected request.
That makes the percentages little conclusive than they first appear. They measurement not only support of AI, but besides the discoverability of a move the browser ne'er shows its users.
Retesting Firefox 155
Firefox 155 arrived connected September 1, and I repeated the measurements the aforesaid day. The trial instrumentality was a MacBookPro11,1, amended known arsenic the 2013 A1502, pinch a cleanable installation of Ubuntu 24.04.3. Firefox 155.0 came arsenic a DEB package from Mozilla’s charismatic repository. Wireshark 4.2.2 captured each traffic, and I decrypted TLS done the SSLKEYLOGFILE situation adaptable arsenic before.
Every browser action took spot visibly successful a existent Xorg convention utilizing rodent and keyboard. There was nary WebDriver, nary distant debugging, and nary prepared Firefox profile. Two factory-fresh profiles formed the 2 series. The A runs covered a acold start, setup followed by idle time, and a fixed browsing script successful the default state. The B runs repeated those steps pinch “Block AI Enhancements” enabled and added a restart of the blocked profile. This clip I explicitly accounted for the methodological trap successful the first test: one-time first-run connections tin look for illustration an effect of the move if they are compared pinch a warmed-up profile. Both acold starts truthful happened earlier anyone touched the switch.
There is bully news up front. Firefox has go quieter connected its very first launch. Where my March trial counted 25 TLS hosts and 76 DNS queries, Firefox 155 produced 14 hosts and 70 queries successful each of the 2 caller profiles. That is simply a existent improvement, but it has thing to do pinch the switch. Comparing the blocked profile’s later nine-host restart pinch the 14-host first motorboat would repetition the aforesaid warm-profile fallacy: the alteration is simply a cache effect, not a blocking effect.
The move has grown
Firefox 155 marks generative AI features arsenic blocked. The power now includes Smart Window and extensions that usage AI supplied by Firefox. Screenshot: Marius Quabeck.Mozilla has expanded the move itself. It now sets eleven preferences alternatively of nine. The additions are browser.ai.control.smartWindow = "blocked" and extensions.ml.enabled = false. The confirmation dialog lists six characteristic areas: translations, PDF alt text, AI tab groups, cardinal points successful nexus previews, Smart Window, and sidebar chatbots. Firefox besides notes that blocking affects extensions that usage AI supplied by Firefox. Extensions whitethorn still interaction outer AI services independently. Mozilla’s documentation remains candid: accepted instrumentality learning for classification, ranking, and personalization is explicitly extracurricular the switch’s remit.
The confirmation dialog names six affected areas, but telemetry, advertising, and research enrollment stay extracurricular the switch’s scope. Screenshot: Marius Quabeck.The biggest caller summation is Smart Window. A week earlier Enzor-DeMeo’s essay, Mozilla formally unveiled the prompt-based browsing situation that had appeared successful preview builds arsenic AI Window. Smart Window combines web hunt from AI hunt supplier Exa, selectable connection models, automatic tab-group suggestions, and a ocular history preview. The beta initially launched successful English for the United States and Canada. It is configured, of each places, wrong the settings sheet that had been marketed arsenic a termination move successful February.
Internally, the characteristic is still called AI Window. Both caller profiles requested a Remote Settings postulation named ai-window-prompts 23 and 24 seconds aft their very first launch. During the B run, the personification was still trapped down Firefox’s mandatory first-run announcement astatine that point; the move was not yet accessible. The first AI-related server petition truthful preceded immoderate opportunity to choose. Consent is asked? Not successful those first 24 seconds.
Telemetry does not understand “blocked”
The astir important nonstop comparison successful the bid was visible setup followed by 120 seconds of idle time, erstwhile successful the default authorities and erstwhile instantly aft blocking AI. The consequence is uneventful, and that is the finding. Both runs contacted 9 TLS SNI hosts. Both sent 14 telemetry POST requests to incoming.telemetry.mozilla.org, pinch precisely the aforesaid class distribution, including 8 messaging-system pings each. Apart from 1 section multicast destination successful the default run, the target database was the same: advertisement servers, Merino, the Settings CDN, telemetry, each present. The move did not region a azygous 1 of those hosts.
| Direct move preferences | 9 | 11; Smart Window and Firefox AI successful extensions added |
| Fresh-profile first launch | 25 TLS hosts, 76 DNS queries | 14 TLS hosts, 70 DNS queries |
| Telemetry aft blocking | Continues | Continues: 14 POSTs while idle, 9 aft restart |
| Persistent identifiers | Remain | Remain, confirmed wrong decrypted pings |
| Advertising and Merino | Remain active | Remain active |
| Temu connection DNS | Present | Present, including aft a blocked restart |
| soloist.ai Sponsored Tile | Consistently present | No longer successful the inventory |
| AI research assignment | Chatbot summarization, curen branch | copilot-chatbot-sunset, power branch; remains aft blocking |
| AI petition earlier move access | Not observed | ai-window-prompts during first launch |
After the blocked floor plan restarted, Firefox sent 9 much POST requests wrong 120 seconds. Their Glean customer ID, bequest customer ID, profile-group ID, and some usage UUIDs were identical to those successful the preceding run. The move rotates thing and deletes nothing. The blocked profile’s newtab ping reported, among different values, pocket.sponsored_stories_enabled = existent and topsites.sponsored_enabled = true, on pinch the partner codification for Google search. The usage ping continued to see the operating system, nonstop kernel, build, distribution, default-browser status, progressive ticks, and some usage UUIDs. This clip the grounds is stronger: I reconstructed 37 complete POST payloads from the decrypted HTTP/2 and HTTP/3 streams.
The move was arsenic inconsequential during existent browsing, astatine slightest wherever information leaving the instrumentality was concerned. The fixed script utilized identical stops pinch hard-checked destination URLs, from kernel.org to a Netzwelt guide. The default floor plan reached 22 TLS hosts; the blocked 1 reached 26. The blocked tally was not moreover quieter. The differences were move debris, an image big here, a consent big there, from which neither a beneficial nor a harmful effect of the move tin beryllium inferred.
Nimbus, Mozilla’s research system, provides the astir ironic result. After restart, its targeting-context ping dutifully reported browser__ai__control__default = "blocked", while keeping the aforesaid floor plan enrolled successful the progressive copilot-chatbot-sunset experiment’s power branch. The matching penchant was still coming successful prefs.js: browser.ml.chat.nimbus = "copilot-chatbot-sunset:control". Being blocked is not an exit from Mozilla’s research system; it becomes different targeting property. The aforesaid ping listed eleven further Smart Window microsurvey, What’s New, and promotion run slugs arsenic NotEnrolled. That does not beryllium information successful those campaigns, but it does show an extended run servants of the state surrounding the AI features.
This is wherever Enzor-DeMeo’s percentages merit a 2nd look. How does Mozilla cognize truthful precisely that 1 percent abnormal everything and 3 percent switched disconnected individual features? Through the aforesaid telemetry the move leaves untouched and which obediently reports the switch’s state. Anyone who presses “Block AI Enhancements” automatically becomes a information constituent successful the CEO’s occurrence story.
Advertising continues, and Temu says hello
Firefox’s advertisement infrastructure is arsenic unmoved by the move arsenic it was successful March. Both idle runs called the preflight endpoint astatine ads.mozilla.org and Merino’s picture-of-the-day API, and each established six TLS handshakes pinch ads-img.mozilla.org. The acquainted connection locator temuaffiliateprogram.pxf.io was prefetched done DNS aft conscionable nether 3 seconds successful some caller profiles and aft a small complete 5 seconds pursuing the blocked restart. Firefox truthful still resolves the search domain of a discount marketplace the personification has ne'er visited, whether AI is blocked aliases not. The captures beryllium DNS prefetching; they do not show a consequent TLS relationship to that host.
One big did disappear: soloist.ai, the AI startup promoted done a Sponsored Tile successful March, appeared successful nary of the 7 valid Firefox 155 captures. The move cannot return the credit, because the big was absent some earlier and aft blocking. The advertizing inventory changed; the advertizing machinery did not.
Tante sounds the essay
My first article drew connected writer and sociotechnologist Jürgen Geuter, known online arsenic tante (@[email protected]), and his effort “Hiding down translations.” Enzor-DeMeo’s caller effort almost repeats tante’s earlier analysis: AI has nary fixed definition, translator is classical instrumentality learning, and generative AI is only 1 subset. Yet the CEO reaches the other conclusion: group near translations enabled. I asked tante to measure the essay.
“Enzor-DeMeo’s article is simply a unusual benignant of PR,” he told me. The CEO uses the isolated condemnation “Almost cipher utilized it” arsenic a lever to deflect disapproval of Mozilla’s AI focus. “But of people the statement is dishonest: group do not spot translator arsenic AI, but Mozilla embedded it successful the button, and truthful AI remains active.” In tante’s view, the termination move does not springiness group the “choice and agency” Enzor-DeMeo claims: “Because that would mean gathering group wherever they are, successful their knowing and needs, alternatively than presenting them pinch a mendacious choice.”
The CEO’s ain nickname that AI is unpopular does not make his lawsuit immoderate stronger successful tante’s view. “But it ne'er occurs to him to make each this crap opt-in. Because AI is his only strategy for a institution that, arsenic a browser maker, ought to attraction much astir the web.”
The astir important switch
To beryllium fair, Firefox is measurably amended than it was successful the spring. According to StatCounter, its marketplace stock roseate from 2.29 percent successful February to 2.98 percent successful August. Its first motorboat is substantially quieter, its AI move covers much features, and the implementation remains sound. The reside from the executive suite is caller too. It has been a agelong clip since a Mozilla CEO publically admitted to missing the message.
Only the bound of the move has not moved by a millimeter. It disables generative features, and thing else. Telemetry continues pinch persistent identifiers. Advertising is delivered, connection domains are resolved, research assignments remain, and the browser contacts its first AI infrastructure earlier the personification tin moreover spot the switch. “The astir important AI characteristic whitethorn beryllium the expertise to move it off,” Enzor-DeMeo writes. The condemnation is true. It simply describes a characteristic Firefox still does not person successful that broader sense. Anyone who earnestly wants to power what the browser sends location still needs about:config, Wireshark, and a patient dose of suspicion.
The adjacent measurement is obvious. A browser that asks connected first motorboat whether its personification wants generative features would lick the discoverability problem identified successful the LinkedIn comments and move “choice and agency” into a genuine opt-in alternatively of a buried opt-out. The method infrastructure exists; the move itself proves that. What is missing is the willingness to consequence proceeding the users’ answer.
The last connection belongs to tante. Enzor-DeMeo concludes that Firefox users taught him thing enormously valuable: that an flight hatch, an option, is the astir important thing. Tante’s reply is brief: “No. The astir important point would beryllium not to build systems that your personification guidelines despises.”
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