Summarization

Intent

The changes aim to address a user request to allow media metadata (such as track title, artist, and album information) to be exposed through system media controls (e.g., MPRIS on Linux) even when the user is in private browsing mode. By default, Firefox suppresses this metadata in private browsing to protect user privacy, but some users may prefer the convenience of seeing media information in their system's media controls regardless of the browsing mode. This patch introduces a preference that lets users opt in to this behavior.

Solution

The solution introduces a new boolean preference, , defaulting to (preserving the existing privacy-respecting behavior). When this preference is set to , the code in that determines whether media metadata should be hidden (by checking if the document is in private browsing) is effectively bypassed. Specifically, in the method that checks whether metadata should be blocked for private browsing contexts, the new code checks the preference value before evaluating the private browsing state of the document. If the preference is enabled, the method returns early (indicating metadata should be exposed), skipping the subsequent private browsing check that would otherwise suppress the metadata. This gives users explicit control over whether their media metadata is visible in system media interfaces during private browsing sessions.

Fix logic bug and update doc comment

LGTM, thanks!