This adds a new parameter ("preferInitialWindowPlacement") to the document picture-in-picture API that, when set to true, hints to the user agent that it should not try to reuse the position or size of the previous document picture-in-picture from this site when opening this one. Often, a document picture-in-picture window will close and re-open multiple times for the same site, such as moving a video conference to and from PiP. The user agent is free to re-open the PiP window at its most recent size / location, so that it stays where the user last moved it and provides continuity between the PiP windows. However, if the new window is semantically unrelated to the previous window, such as if it is a new VC, then the developer can use this parameter provide a hint to the user agent that this window might be better opened in its default position / size instead.
Often, a document picture-in-picture window will close and re-open multiple times for the same site, such as moving a video conference to and from PiP. The user agent is free to re-open the PiP window at its most recent size / location, so that it stays where the user last moved it and provides continuity between the PiP windows. However, if the new window is semantically unrelated to the previous window, such as if it is a new VC, then the developer can use this parameter provide a hint to the user agent that this window might be better opened in its default position / size instead.