GitHub (disclosure: where I work) does respect some directives in a repo’s .gitattributes file. For example, you can use them to override language detection or mark files as generated or vendored to change diff presentation. You can also improve the diff hunk headers we generate by default by specifying e.g. `*.rb diff=ruby` (although come to think of it I don’t know why that’s necessary since we already know the filetype — I’ll look into it)
In principal there’s no reason we couldn’t extend our existing rich diff support used for diffing things like images to enhance the presentation of lockfile diffs. There’s not a huge benefit for text-based lock files but for binary ones (if such a scheme were to take off) it would be a lot more useful.