Browser Extension — Privacy (Version 4, 2026-10-24)

This is a copy of https://buboflash.com/bubo5/tal-static-fullscreen-forall/annotations-privacy, which is the authoritative version.

The Buboflash extension lets you select a passage on any webpage and turn it into an annotation or a flashcard, or mark a place on the page with a bookmark to come back to. It shows you your highlights and bookmarks when you come back to that page, and lists them in a side panel beside it.

To show you your old highlights it has to ask our server "do I have anything for this page?" — and to ask that, it has to tell the server which page you are on. That is the whole privacy trade, and everything below is detail on it.

1. The switch is real

Annotations in tabs is a checkbox in the extension's popup. The toolbar icon shows its state: crossed out when it is off or you are not logged in, plain when it is on.

When it is off — or when you are not logged in to Buboflash — the extension sends nothing about your browsing. Not the URL, not the page, nothing. It does not even load itself into the page: with the switch off no script is injected into any tab, so there is nothing running there to send anything.

What it still asks our server, switched off, is whether you are logged in, and — when you open the popup — for a summary of your learning and your Annotations from choice (§ 5). None of these says anything about the page you are on.

This is a gate in the code and not a promise about intent. It is checked every time the extension is about to send a page's address or anything taken from the page, creating something and placing a bookmark included.

1. When it is on, and you are logged in

The address of every page you open is sent to the Buboflash server, apart from the pages in § 4. It is sent when the page loads, for two questions:

1. Can this page be annotated at all? — some pages are excluded (see § 4).
2. What do you have on this page? — your annotations, flashcards and bookmarks on it, so that they can be shown there.

The second question is asked again while you use the page: when you come back to its tab (at most once every three seconds), after you create or change something there, when the page moves to a new address without reloading, and when you change Annotations from. The address also goes with everything you create or re-attach on the page and with every bookmark you place there (§ 3), and when you switch the selection bubble off or on for its site (§ 5).

The page itself is not sent. We send the address; the server answers with your own annotations for it; the extension then finds the matching passages inside your browser and highlights them there. The server never sees the text it is highlighting, and asking about a page never makes our server fetch it.

So if you open your bank, your medical records or your employer's intranet with the extension on, what reaches us is the address of the page and nothing that is on it. That holds even if somebody else has maliciously created an annotation on a page with the same address — the matching happens in your browser, and the annotation text is theirs, not your page's.

But an address is not nothing. https://example-clinic.co.uk/results/appointment-confirmed tells a reader a great deal without a single word of the page body. Please read § 3 and § 8 with that in mind.

1. When you actually create something

Creating an annotation, a flashcard or an occlusion card from a selection sends us, in addition to the address:

• the text you selected, and its HTML;
• a flashcard's other side, if you typed it or selected it on the page;
• a short window of the surrounding page — at most 256 characters before your selection and 192 after it — so the passage can be located again if the page changes, and so its context can be shown, for instance in search results. The count includes the page's markup, so the text in a window is usually a little shorter. It is the page's text as written, which can include words the page does not display, such as labels meant only for screen readers;
• which occurrence it is, if the same text appears several times on the page, and how many occurrences there are.

An occlusion card made inside a passage sends that passage as well — the part you selected first, with the words you blanked out marked in it — and a second window around it, bounded the same way. Re-attaching an annotation to a different passage sends the new passage and its window in the same way.

A bookmark marks a place on the page rather than a passage, so you need not select anything to place one. Placing a bookmark — from the selection bubble, the right-click menu, the side panel or the keyboard — sends, in addition to the address:

• a short window of the page's text on either side of the place — at most 256 characters before it and 192 after it — so the bookmark can be found again when you come back. It is the page's text, and like the windows above it can include words the page does not display;
• how far through the page's text the place lies, so that if the page has changed too much for the bookmark to be found, you can still be taken near where it was.

Moving a bookmark sends the same about its new place. Its note is sent when you write one. Deleting a bookmark, or undoing a change to one, sends only which bookmark it is. Placing a bookmark does not make our server fetch the page or keep any of its text beyond those two windows.

Those windows, around a selection or a bookmark, are the only page content we receive that you did not select yourself, and they are bounded. We do not receive the rest of the page. What our server does with a page you annotate — it fetches the page from its site and keeps the text it extracts, so that your material can be searched — is in the Privacy Notice (https://buboflash.com/bubo5/tal-static-fullscreen-forall/privacy) § 2f.

1. Pages the extension will not touch

These are decided in your browser, from the address alone, so their addresses are never sent:

• Buboflash's own pages. You do not need the extension there.
• A search engine's results page on Google, Bing, DuckDuckGo, Yahoo, Yandex, Baidu, Ecosia, Startpage, Brave Search or Kagi, because its address carries what you searched for. The engines' other pages are treated like any page.
• mail.google.com, whose addresses identify your messages. Our server refuses it as well.
• Anything that is not http: or https: — local files, browser settings pages, extension pages.
• Your settings — and the ones that are not local

Stored in your browser, per browser (so you can have the extension on at home and off at work): the Annotations in tabs switch itself, and your keyboard shortcuts, which you set in the browser's own extension settings. While the browser is open the extension also keeps a few working notes there — whether you are logged in, and which tabs it is working in — which the browser clears when it closes.

Stored on your Buboflash account, shared across every browser:

• Annotations from, which chooses whose annotations you see;
• how long a highlight's popup stays open after the pointer leaves it, which is one of Buboflash's own settings;
• the sites on which you have switched the selection bubble off. The bubble is the small bar that appears when you select text, and the popup lets you switch it off for the site you are on. To remember that, our server keeps the site's name — en.wikipedia.org, never the rest of the address — with your account until you switch it back on there. On such a site you can still create from the right-click menu or the keyboard.
• The side panel, the popup and our website

The side panel (in Firefox, the sidebar) lists the annotations and bookmarks on the page in the tab beside it — the same ones shown on the page, which the extension already holds — so opening it sends nothing more about the page than a request for the page's tags, by our own number for that page.

The popup shows what the extension knows about the page in front of you only while the switch is on and you are logged in. With the switch off it shows only a summary of your learning, with no connection to the page you are browsing.

In Chrome, and in the browsers built on it, our own website can ask whether the extension is installed, so that it stops offering it to you. No other website can. Firefox lets no website ask, so there our website goes on offering the extension after you have installed it.

1. What the page you are reading can see

The extension's highlights and controls are drawn inside the page you are reading, and that page's own scripts share the browser window with them. We keep our controls sealed off from the page's code as far as browsers allow, but some things cannot be hidden from it:

• Your highlights. They are marks in the page's own text, so the page can see which passages you have highlighted on it, and our number for each.
• What you type over it. While you type into the extension over a page — a flashcard's question or answer, an edit to an annotation, a bookmark's note — the page can see the keys you press. If that matters on a page, create the card and finish it on the Buboflash website instead.
• The pictures and sounds in your cards. Those shown over a page are loaded by that page, so it can see where they are on our server, and open them. Our server keeps no record of which page they were shown on.
• Text you select inside a card shown over the page, in some browsers.
• Please do not install this at work or school

Sending the address of every page you open to an outside server is almost certainly against your employer's or your school's policy, whatever the server does with it. You may also get buboflash.com blocked by whoever runs the firewall, which would be a bad outcome for both of us.

If you want to learn from something at work, use buboflash.com directly. Nothing in the extension is unavailable there.

1. What happens to the addresses afterwards

Nothing, unless you create something on the page or place a bookmark there — its address then becomes part of what you made — or switch the selection bubble off for its site (§ 5). The address is removed from our server's request log before the log is written, and the log itself is deleted after 14 days; what it keeps is that your extension asked, when, and for which account. The one exception is a failure: if our server fails while answering your extension about a page, the record of the failure, which we keep in order to fix it, can include that page's address. It is deleted with the other logs, after 14 days. Apart from that, we keep no record of your browsing. The Privacy Notice (https://buboflash.com/bubo5/tal-static-fullscreen-forall/privacy) § 5 and § 8 give the detail.

1. Where else to look
2. Privacy Notice (https://buboflash.com/bubo5/tal-static-fullscreen-forall/privacy) — the whole service, not just the extension.
3. Terms of Service (https://buboflash.com/bubo5/tal-static-fullscreen-forall/toc)
4. Your Freedom Matters (https://buboflash.com/bubo5/tal-static-fullscreen-forall/your-freedom-matters)