How to render control characters/How to render BibTeX

There are numerous applications which use citeproc-php in order to provide a BibTeX format export. For BibTeX (as well as Endnote or something similar) it’s important to render control characters like newlines or tabs. CSL does not support this feature (to my knowledge). And I have no idea how to improve citeproc-php to render “beautified” BibTeX.

This missing feature leads to missing necessary parentheses since several consecutive characters will be removed by citeproc-php because they must be removed for other styles. On the one hand newlines would help to beautify the output for some styles and on the other hand it would solve the problem with the missing curly bracket inherently.

Anyhow, I’m looking for a way to define newlines in citation styles and how to render them. Have any one any ideas? How you solved these issues with other processors?

Thanks in advance,

Some test cases of citeproc-js use 
 which seems to work.