The injector removes empty lines from the HTML. This which isn't website-breaking, but does adversely affect readability of the HTML. On a related, readability note, it would be nice to add an additional linefeed to the end of the injected HTML, so that the </head> tag is still on its own line after injection.
I traced it through the code, and it looks like the Metaparser is what is removing the empty lines, so this would presumably also require adding options to rfg-api, and Metaparser. It seems like these are all maintained by the same people, so I am only raising the issue here for now, until I get some feedback.