We explicitly do not want to support the all-caps BUG: format, as it does not follow the convention of existing well-enshrined git trailers (Signed-off-by, Reviewed-by, Change-Id, and more. You can see the official trailer documentation here[1] and a list of commonly accepted trailers here[2].

[1] https://git-scm.com/docs/git-interpret-trailers
[2] https://git.wiki.kernel.org/index.php/CommitMessageConventions

Thanks for the clarification! I didn't know those tags are expected to follow the trailer pattern.