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Semantic History Search Test Days Event

21 Julho - 01 Agosto 2025

Firefox is introducing Semantic History Search, a new feature that makes it easier to search your Firefox history by understanding the meaning and context, instead of relying solely on keywords. Built on a vector-based model, it offers a more intuitive browsing experience while keeping your data private by processing everything locally on your device.

With the release of Firefox Beta 142, Mozilla’s community will be among the first to experience this new feature and provide feedback directly to the team behind it. Your input will help shape the feature while it’s still in development. 

This event is organized by Mozilla Support in collaboration with Firefox QA. Mozilla Support is a global community of enthusiastic volunteers and staff working together to help users through the community forums, help articles, and article localization.

Join the Test Days

Step 1: Enable the pref & restart

Open your Firefox Beta, go to about:config, and type messaging-system-action.testday, select string type, click + at the end of the line, and set the value to “testday”. Restart your browser for the change to take effect. Upon restarting, a modal window will appear when you open a New Tab and welcome you to the Mozilla Test Days.

Step 2: Submit live feedback & report issues

Type anything in the address bar to trigger a suggestion. But note that Firefox will need 5-10 mins (depending on the size of your history) to trigger the semantic database construction. Semantic suggestions will be marked with an ‘S’ icon. Once you get the semantic search result, let us know if the suggestions match your expectations based on your search keywords by filling out this feedback form. And if you encounter any issues or unusual behavior, please report them using this report form.

Step 3 (optional): Submit general feedback

At the end of the campaign, you’ll have the opportunity to share general feedback about the functionality and the test days event in general by following the prompt in your browser’s new tab page.

Requirements

  • User is enrolled in Test Days Event
  • Minimum RAM size – 8GB
  • In about:config value for browser.ml.enable is true (default value)
  • Semantic database is created and populated (see below for more instruction)

How semantic suggesntions works

How to create an adaptive history entry

How to file a bug report

  1. Create a Bugzilla account and log in. You can also use your GitHub account to log in.
  2. Access this link and tell us more detail about the issue. Include a summary, steps to reproduce the issue, expected result, and the actual result.
  3. If you want to share  screenshots or screen recordings, you can click on the ‘Attach New File’ button and upload your attachment (please note that the size limit is 10MB).
  4. We know Bugzilla can be overwhelming, so if you’re still confused about where to start, you may want to take a look at this sample bug.
  5. More about bug writing guidelines can be found here.

Frequently Asked Questions

Q: Are there any specific test cases?

A: Instead of following rigid test cases, we encourage you to browse as you normally would. This allows us to gather insights on how the new semantic history search experience fits into your everyday browsing habits, ensuring that it aligns with real-world usage.

Q: I am new into using Firefox Beta, what can I do to improve my search experience? 

A: If you are a new Firefox user, consider importing your history and other browsing data from your previous browser (check out this article to learn more about importing data from another browser into Firefox).

If you’re an existing Firefox user on another release channel, consider logging in with your Mozilla account if you have one to sync your Firefox data across devices (e.g. Firefox Desktop and Firefox on your mobile phone) and release channels (e.g. Firefox Beta and Firefox Nightly). That’ll help you access your existing data, such as browsing history, open tabs, etc, and help you browse seamlessly across devices.

Q: Can we trigger the semantic database construction manually? 

A: You can do so by following the steps below:

  1. Open Firefox, in a new tab type “about:config” and accept the risk to continue
  2. In the preference search bar type: places.loglevel
  3. Replace the ‘Error’ text with ‘All’
  4. Restart Firefox for changes to apply
  5. (Optional) If there is no history on your profile, open at least 5-6 websites
  6. Open a new tab and input any search term in the address bar to trigger suggestions and arm the vector database update task

Here‘s a video demo on how you can do that.