Page presets

A preset is part of the session configuration. It applies to the task tabs the session owns, including tabs it opens later.

anti-adnone

Set a presetCopy Anchor Link

const browser = await connect("archive");

await browser.preset("anti-ad", { environment: true });
await browser.navigate("https://example.com");

const status = await browser.call("preset", { cmd: "status" });
console.log(status);

preset stores the configuration for the session and applies it to the tabs the session owns. navigate accepts the same preset, zen and environment fields. It stores them once the navigation starts. From the command line:

omw call archive preset '{"preset":"zen","zen":{"images":true,"fonts":true,"css":false,"javascript":false}}'
omw call archive preset '{"cmd":"status"}'

A session that has not selected a preset uses anti-ad, the default for new task tabs.

anti-adCopy Anchor Link

The lists are compiled into the extension at build time. pnpm run filters:update downloads them and records the URL, SHA-256 value, date and original notices in third_party/filters/sources.lock.json. The extension does not fetch rules or updates from a third-party server, and it works offline.

Included lists:

• AdGuard Base, with the EasyList duplicates removed, and AdGuard Tracking Protection
• EasyList and EasyPrivacy
• The enabled, non-regional default lists of uBlock Origin: filters, badware, privacy, unbreak, quick fixes, URLHaus and Peter Lowe

Regional lists and annoyance lists are not included. Packaged uBO scriptlets and redirect resources come from Ghostery's pinned copy.

The engine implements request blocking and exceptions. Redirects, response body and HTML rewriting, CSP directives and procedural cosmetics are not implemented. A page can therefore render differently than it does under uBlock Origin or AdGuard with the same lists.

zenCopy Anchor Link

zen adds resource type blocking to anti-ad. Each switch is a boolean, and true blocks that resource type.

javascript: true also stops inline scripts and event handler attributes. In Chrome, script execution is disabled through CDP. In Firefox, the extension adds Content-Security-Policy: script-src 'none' to the document and iframe responses of the tab. <noscript> content then does not render, because the browser still reports scripting as enabled.

The restrictions cover network requests. Inline and data images, inline CSS and installed service worker caches are not affected. A site that needs stylesheets or scripts breaks under these switches. Select none or relax a switch and navigate again.

environmentCopy Anchor Link

environment: true adds cosmetics and scriptlets from the bundled lists, guarded by the document hostname. It is off by default, and skipped in zen while javascript is on.

Registration happens before the target document loads, so the setting applies to the next document the tab shows. It does not alter a page that is already loaded. Navigate again. A cross-host redirect or an iframe from another host receives network filtering only, because the guard never injects a different host's rules.

Environment injection is not anti-bot fingerprint spoofing. A scriptlet that fails to parse or throws affects only itself. Status reports installation, not successful execution of every scriptlet. In Firefox, environment: true is accepted but reported as environmentState: "unavailable", and network filtering continues.

noneCopy Anchor Link

none removes interception from task tabs. A raw CDP Fetch handler installed through cdp conflicts with a preset request handler on the same tab. Select none first.

Borrowed tabsCopy Anchor Link

Presets apply only to tabs the session owns. A borrowed tab is never filtered, and it keeps no preset state for the session that borrowed it. Preset options on a navigation that targets a borrowed tab return borrowed_tab.

StatusCopy Anchor Link

preset {cmd:"status"} reads the current tab and returns:

• the configuration: name, environment, images, fonts, css, javascript
• blocked and allowed request counts since the preset was installed
• network, whether interception is active on the tab
• environmentState: off, active or unavailable
• fallback, up to 8 reasons, each cut to 300 characters

Any other cmd value returns invalid_args. A configuration call returns config, a status entry for each task tab, appliesOn and borrowedTabsExcluded. appliesOn is immediate; environment on next navigation in Chrome.

Costs and limitsCopy Anchor Link

• Matching runs in the extension background, in one filter engine shared by every tab. Requests are not sent to the daemon.
• Engine data is released 30 seconds after the last filtered tab stops filtering. The next preset loads it again.
• Network and script restrictions apply to existing task tabs and frames immediately. Environment registration applies to the next document.
• Reconfiguring a tab disables interception on every target of the tab first, so page requests continue while a busy frame delays the rest. Installing the new preset needs the current document to answer. Use close_session to recover an unresponsive page.
• Navigating a task tab whose preset did not change keeps the interception and sends no reconfiguration commands. With environment off, status counters continue across the navigation.
• If the lists fail to load, requests pass unfiltered and status keeps the reason. zen type blocking still applies.
• Chrome intercepts at most 128 targets per tab. Additional frames fail open and status records the reason. Firefox has no per-tab target limit.
• When Chrome restarts the extension worker, status reports none for existing tabs until a controlled navigation reapplies the stored session configuration. No site action is retried.
• pnpm run filters:update downloads the upstream lists, updates the gzip files and sources.lock.json, and fails on a download error or an invalid response. The build fails on an integrity mismatch between a list and its recorded SHA-256.

FirefoxCopy Anchor Link

The Firefox build uses the same modes, lists and session settings. Network filtering runs in blocking webRequest listeners, environment injection is unavailable, and a blocked top-level page keeps the tab on its current page. Firefox covers the differences.