In version 2.57.1049 regretfully the file 'lang_changes.txt' nor the English language file have been updated (still concern 2.57.1046).
However translators should know that at least one addition should be made for version 2.57.1049 under
//Preferences, Video
[WID10]
i.e.:
133=Video background colour
(I already put it in my Dutch language file)