Reference answers to various topics seen in the wild

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• Does uBO download filter lists at launch?
• Is a manually-installed uBO better and more performant?
• Should I disable "Suspend network activity until all filter lists are loaded" in uBO for Firefox/Firefox for Android?
• Does uBO use service workers?
• Does uBO open tabs on its own?

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Does uBO download filter lists at launch?

No, uBO does not download filter lists at launch, it just uses filter lists currently cached in its storage, and typically will even load from a memory snapshot created in the previous session to ensure quick readiness, and uBO will be ready in a fraction of second after launch. You can see how long it took uBO to be ready after launch by going to the Support tab in the dashboard, look up allReadyAfter in troubleshooting information.

Filter lists are updated in a lazy way in the background after launch. Once the filter lists have all been updated in the background, they are reloaded into memory. Subsequently a memory snapshot will be created to ensure fast load time next time uBO is launched.

_{https://old.reddit.com/r/firefox/comments/1euljyd/comment/limy0jg/}

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Is a manually-installed uBO better and more performant?

No. Placebo-effect.

uBO with the same exact configuration will behave the same whether manually-installed or webstore-installed.

Whoever wants to argue about this can prove it using your browser's profiling tools, otherwise it's just an uninformed opinion.

_{https://old.reddit.com/r/uBlockOrigin/comments/1b8ryuz/is_this_true/}

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Should I disable "Suspend network activity until all filter lists are loaded" in uBO for Firefox/Firefox for Android?

No.

Doing so will prevent uBO from properly filtering the first webpage loaded at launch time because this tells uBO to let all network requests through before the filter lists are loaded into memory. If this setting was of no importance, it would not be enabled by default.

Waiting for filter lists to be loaded in memory is a one-time event when uBO launches, and this may cause a delay when loading the first webpage at launch time. Once the filter lists are all loaded in memory, the setting has no effect on how fast webpages load.

Do not follow random advice of people suggesting that you disable this setting, especially when they do not provide information on the adverse effects of doing so, they most likely lack the technical knowledge behind the setting, and are failing to ensure you are making an informed choice.

You can find out how long it takes for uBO to be fully ready by opening the Support pane in the dashboard and by finding the allReadyAfter entry at the bottom of the troubleshooting information section. Work is being done to reduce that initial delay.

_{https://old.reddit.com/r/firefox/comments/1b4n48c/firefox_on_android_runs_much_better_after/}

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Does uBO use service workers?

No.

uBO doesn't use service workers, it uses dedicated workers -- and just for the time it needs it -- to avoid blocking the user interface while performing CPU-intensive tasks. For examples:

• To search strings in asset viewer
• To reverse-lookup lists in logger
• To apply patches in differential updater
• To serialize/deserialize/compress/decompress large lists downloaded from remote servers and memory snapshots

_{https://old.reddit.com/r/uBlockOrigin/comments/1b36y1l/service_workers_should_i_continue_to_block/}

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Does uBO open tabs on its own?

No.

If a tab opens and uBO tells you that it blocked navigation to some URLs, something else than uBO opened the tab, and uBO merely blocked the navigation because of a filter from one of the filter lists matched.

Tabs can be created by websites or other extensions, uBO never ever creates a tab, except to its own internal pages and only when you specifically ask for it (for example when you click the "gear" icon in the popup panel.

_{https://old.reddit.com/r/uBlockOrigin/comments/1b3anva/why_is_ublock_origin_creating_pinned_tabs_in/}

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