I would like to add in the title field of some bib entries a dummy command which I can redefine to force e.g. a linebreak in certain cases. I need a command which normally doesn't do anything, doesn't rely on some specific package (so that the bib-file doesn't break when used without the package), which isn't used elsewhere and which I can safely redefine without breaking something.
I looked up latex.ltx but couldn't find anything suitable. Has someone an idea what I could use if I don't want to clutter the bib with