The source project of this merge request has been removed.
You might want to fix it the same way as I did in https://code.briarproject.org/nicoalt/briar-gtk/commit/4d1acc7c4c278ece5cb4e920a38d9910d70b5b95, and not like I did here quickly for the video to work.
Related to briar/briar#1677 (closed)