[BossingAround]

> It's unclear to me why this is not the default

It's literally in the PR you mention:

syntax-highlighting very long lines (e.g. minified .js) will be very slow if they are not truncated

[CGamesPlay]

If you read the comments, you’ll find https://github.com/dandavison/delta/pull/1746 which adds the option I mentioned, which limits the length of syntax highlighting, but still has a rather low limit on maximum (unhighlighted) line length :)