This is an umbrella bug to remove all references to racist terminology in the WebKit Open Source Project.
Bug title and description here make this sound more ambitious than it is. I believe this particular bug tracks a first round of removing some of the most obviously non-inclusive terms: "black/whitelist", "slave/master".
I imagine longer term we will find even more terminology we decide to remove.
https://bugs.webkit.org/show_bug.cgi?id=214942 added a tool, report-non-inclusive-language to help with this effort.