Blast Phemur* privacy

Version 0.2.0 · Updated 31 October 2026

Blast Phemur collects nothing and sends nothing. There is no account, no analytics and no server of ours involved. Everything it does happens in your browser.

What it does

Blast Phemur mutes blasphemy and swearing on streaming video, and masks those words in the captions. It finds the words in the show's own captions, compares them with word lists that ship inside the extension, and lowers the video's volume for the moment a word is spoken.

What it reads

• Captions on the page, on the streaming sites it is allowed to run on, to find the words to mute.
• On YouTube and YouTube TV, the caption file the player already uses. A small script asks the YouTube player for it, from YouTube's own servers and with your YouTube sign-in, the same way the player does. This lets it time each word to the moment it is spoken.
• Subtitle files you add yourself, if you choose to.

None of this leaves your browser. Blast Phemur makes no requests to any server of its own.

What it keeps, on your device only

• Your settings: what to mute, and your own Always mute and Never mute lists.
• Passed moments ("That was fine here"): the show the moment was in (its caption track, or the page address and program name) and a time, so that one moment plays next time. These are the only titles Blast Phemur keeps, and only for moments you passed.
• Subtitle files you added.

The support report copies a short timeline of this tab to your clipboard, with every filtered word masked. It is kept in memory only, and it goes nowhere unless you paste it somewhere yourself.

Removing the extension removes all of it.

What it never does

• No analytics, telemetry, tracking pixels or crash reporting.
• No viewing history. The only titles it keeps are the ones where you passed a moment, as above.
• No selling or sharing of anything, with anyone.

Permissions, and why

• Streaming sites (YouTube TV, YouTube and DIRECTV Stream): to read captions and lower the volume on those pages only.
• Storage and unlimited storage: your settings, and subtitle files, which can be large.
• Scripting: to connect tabs that were already open when Blast Phemur was installed or updated, so you do not have to reload them.

Children

Blast Phemur collects no information from anyone, children included.

Changes to this page

If an update changes what Blast Phemur reads, keeps or sends, this page changes in the same update and the date above moves.

Chrome Web Store user data policy

Blast Phemur's use of information follows the Chrome Web Store User Data Policy, including the Limited Use requirements.

Checking this for yourself

The code is public, under the GNU General Public License version 3 or later, at github.com/MediatrixLibre/blast-phemur. Every claim on this page can be read in the source rather than taken on trust.

Questions

Write to mediatrixdev@proton.me, or open an issue at github.com/MediatrixLibre/blast-phemur.