SponsorBlock blocks System Media Transport Controls (SMTC) on Firefox

[totolford]

Problem

SponsorBlock completely blocks System Media Transport Controls (SMTC) on Firefox. Windows system media control buttons (play, pause, next, previous) no longer work when playing YouTube videos with SponsorBlock enabled.

Steps to reproduce

1. Install SponsorBlock on Firefox
2. Open a YouTube video
3. Try to use system media controls (media keyboard buttons or Windows media controls)
4. System controls do not respond

Expected behavior

System media controls should work normally, regardless of whether SponsorBlock is enabled.

Actual behavior

System media controls are completely non-functional when SponsorBlock is enabled on Firefox.

Verification

• Issue confirmed on Firefox (tested on multiple devices and versions)
• Disabling the SponsorBlock extension makes SMTC work correctly
• Re-enabling the extension causes SMTC to stop working
• This does not affect other SponsorBlock functionality

Environment

• Browser: Firefox
• Platform: Windows (and potentially others)
• Extension: SponsorBlock (version to specify)

The extension appears to interfere with the browser's Media Session API or system-level media control events.

Generate with Copilot.